[Auth] Fix IG4 group type (mlrun#9242)

### 📝 Description

IG4 Authentication client was using the wrong Group gRPC schema type to
extract the user's group from the authentication endpoint response (`GET
/self`).

As can be seen here, the correct type is `usergroup.Group` and not
`group.Group`, as `group` is a reserved gRPC word:
```json
    {
        "metadata": {
            "id": "4ea81f45-37b2-49ed-b776-7aa3ae7af44b",
            "resourceType": "user",
            "username": "normal-user"
        },
        "relationships": [
            {
                "@type": "type.googleapis.com/usergroup.Group",
                "metadata": {
                    "id": "f464c016-65ae-431b-8d3a-b563c59a187b",
                    "path": "/test-group"
                },
                "spec": {
                    "name": "test-group"
                }
            }
        ],
        "spec": {
            "email": "normal-user@iguazio.com",
            "firstName": "normal-user",
            "lastName": "normal-user"
        },
        "status": {
            "active": true,
            "createdAt": "2026-01-21T09:44:58.668Z",
            "ctx": "a2e839df739960d54e13f4f7fe2127cb",
            "groupIds": [
                "f464c016-65ae-431b-8d3a-b563c59a187b"
            ],
            "lastActivity": "2026-01-25T14:40:13Z",
            "lastLogin": "2026-01-25T14:25:29Z",
            "statusCode": 200
        }
    }
```

---

### 🛠️ Changes Made

- `server/py/framework/utils/clients/iguazio/v4.py` : changed the
`_GROUP_TYPE_VALUE` constant to the correct type.

---

### ✅ Checklist
- [ ] I updated the documentation (if applicable)
- [x] I have tested the changes in this PR
- [ ] I confirmed whether my changes are covered by system tests
- [ ] If yes, I ran all relevant system tests and ensured they passed
before submitting this PR
- [ ] I updated existing system tests and/or added new ones if needed to
cover my changes
- [ ] If I introduced a deprecation:
  - [ ] I followed the [Deprecation Guidelines](./DEPRECATION.md)
  - [ ] I updated the relevant Jira ticket for documentation

---

### 🧪 Testing

Using the `iguazio` client:
1. Created a user and a group
2. Assigned user to group
3. Created project
4. Assigned group as project Admin
5. Performed operations as the user - Success :white_check_mark:

---

### 🔗 References
- Ticket link: https://iguazio.atlassian.net/browse/IG4-1184
- Orca schema definition:
https://github.com/iguazio/orca/blob/9f5818389844549e4b878cd885f8f5f992ae87e2/backend/proto/v1/resources/usergroup.proto#L10

---

### 🚨 Breaking Changes?

- [ ] Yes (explain below)
- [x] No

<!-- If yes, describe what needs to be changed downstream: -->

---

### 🔍️ Additional Notes
<!-- Anything else reviewers should know (follow-up tasks, known issues,
affected areas etc.). -->
<!-- ### 📸 Screenshots / Logs -->

Author: TomerShor

server/py/framework/utils/clients/iguazio/v4.py

@@ -35,7 +35,7 @@
 from framework.utils.clients.iguazio.base import BaseAsyncClient, BaseClient
 
 _GROUP_TYPE_KEY = "@type"
-_GROUP_TYPE_VALUE = "type.googleapis.com/group.Group"
+_GROUP_TYPE_VALUE = "type.googleapis.com/usergroup.Group"
 
 
 class Client(BaseClient, project_follower.Member):

server/py/services/api/tests/unit/utils/clients/iguazio/test_iguazio_v4.py

@@ -143,7 +143,7 @@ def _verify_session_with_body_mock(*args, **kwargs):
             "metadata": {},
             "relationships": [
                 {
-                    "@type": "type.googleapis.com/group.Group",
+                    "@type": "type.googleapis.com/usergroup.Group",
                     "metadata": {
                         "id": "dummy-group-id-g1",
                     },
@@ -155,7 +155,7 @@ def _verify_session_with_body_mock(*args, **kwargs):
             "metadata": {"username": "dummy-user"},
             "relationships": [
                 {
-                    "@type": "type.googleapis.com/group.Group",
+                    "@type": "type.googleapis.com/usergroup.Group",
                     "metadata": {"id": "dummy-group-id-g1"},
                 },
             ],
@@ -165,7 +165,7 @@ def _verify_session_with_body_mock(*args, **kwargs):
             "metadata": "not-a-dict",
             "relationships": [
                 {
-                    "@type": "type.googleapis.com/group.Group",
+                    "@type": "type.googleapis.com/usergroup.Group",
                     "metadata": {
                         "id": "dummy-group-id-g1",
                     },
@@ -307,7 +307,7 @@ async def test_verify_request_session_single_group_untyped(
         "metadata": {"username": "dummy-user", "id": "dummy-id"},
         "relationships": [
             {
-                "@type": "type.googleapis.com/group.Group",
+                "@type": "type.googleapis.com/usergroup.Group",
                 "metadata": {"id": "valid-group-id"},
             },
             {
@@ -343,7 +343,7 @@ def sample_user_info(username="dummy-user", user_id="dummy-user-id", group_ids=N
         "metadata": {"resourceType": "user", "username": username, "id": user_id},
         "relationships": [
             {
-                "@type": "type.googleapis.com/group.Group",
+                "@type": "type.googleapis.com/usergroup.Group",
                 "metadata": {"id": gid},
             }
             for gid in group_ids
@@ -727,11 +727,11 @@ def _generate_igv4_httpx_exception(
                 },
                 "relationships": [
                     {
-                        "@type": "type.googleapis.com/group.Group",
+                        "@type": "type.googleapis.com/usergroup.Group",
                         "metadata": {"id": "group1"},
                     },
                     {
-                        "@type": "type.googleapis.com/group.Group",
+                        "@type": "type.googleapis.com/usergroup.Group",
                         "metadata": {"id": "group2"},
                     },
                 ],