fix(BA-5709): keep delegate_endpoint_ownership signature in slice A

Slice A scope is only the new get_main_access_key_by_id helper and the
SessionConditions rewrite. Accidentally dropping the
target_main_access_key argument from delegate_endpoint_ownership
belongs to a later slice that also updates EndpointRow and the user
service; restoring the signature here so this PR builds standalone.

Author: jopemachine

src/ai/backend/manager/repositories/user/db_source/db_source.py

@@ -17,7 +17,7 @@
 
 from ai.backend.common.clients.valkey_client.valkey_stat.client import ValkeyStatClient
 from ai.backend.common.data.permission.types import RBACElementType
-from ai.backend.common.types import VFolderID
+from ai.backend.common.types import AccessKey, VFolderID
 from ai.backend.logging.utils import BraceStyleAdapter
 from ai.backend.manager.data.common.types import SearchResult
 from ai.backend.manager.data.keypair.types import (
@@ -672,10 +672,13 @@ async def delegate_endpoint_ownership(
         self,
         user_uuid: UUID,
         target_user_uuid: UUID,
+        target_main_access_key: AccessKey,
     ) -> None:
         """Delegate endpoint ownership to another user."""
         async with self._db.begin_session() as session:
-            await EndpointRow.delegate_endpoint_ownership(session, user_uuid, target_user_uuid)
+            await EndpointRow.delegate_endpoint_ownership(
+                session, user_uuid, target_user_uuid, target_main_access_key
+            )
 
     async def delete_endpoints(
         self,

src/ai/backend/manager/repositories/user/repository.py

@@ -16,7 +16,7 @@
 from ai.backend.common.resilience.policies.metrics import MetricArgs, MetricPolicy
 from ai.backend.common.resilience.policies.retry import BackoffStrategy, RetryArgs, RetryPolicy
 from ai.backend.common.resilience.resilience import Resilience
-from ai.backend.common.types import SlotName
+from ai.backend.common.types import AccessKey, SlotName
 from ai.backend.common.utils import nmget
 from ai.backend.logging.utils import BraceStyleAdapter
 from ai.backend.manager.data.common.types import SearchResult
@@ -191,9 +191,12 @@ async def delegate_endpoint_ownership(
         self,
         user_uuid: UUID,
         target_user_uuid: UUID,
+        target_main_access_key: AccessKey,
     ) -> None:
         """Delegate endpoint ownership to another user."""
-        await self._db_source.delegate_endpoint_ownership(user_uuid, target_user_uuid)
+        await self._db_source.delegate_endpoint_ownership(
+            user_uuid, target_user_uuid, target_main_access_key
+        )
 
     @user_repository_resilience.apply()
     async def delete_endpoints(