Add listIndexes to unexplainable MongoDB commands (DataDog#22825)

* [SDBM-2431] Add listIndexes to unexplainable commands

listIndexes cannot be explained by MongoDB and results in
IllegalOperation errors. Adding it to UNEXPLAINABLE_COMMANDS
prevents the integration from attempting to explain it.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

* Rename changelog entry to match PR number

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

* Update changelog to be more customer-facing

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

---------

Co-authored-by: Claude Opus 4.6 <noreply@anthropic.com>

Author: pierreln-dd

mongo/changelog.d/22825.fixed

@@ -0,0 +1 @@
+Fix ``IllegalOperation`` errors in DBM explain plans caused by attempting to explain ``listIndexes`` commands.

mongo/datadog_checks/mongo/dbm/utils.py

@@ -57,6 +57,7 @@
         "profile",  # command to get profile level
         "listCollections",
         "listDatabases",
+        "listIndexes",
         'dbStats',
         'createIndexes',
         'shardCollection',

mongo/tests/test_unit.py

@@ -899,6 +899,13 @@ def load_json_fixture(name):
             True,
             id='ns with no collection',
         ),
+        pytest.param(
+            "test.test",
+            "command",
+            {"listIndexes": "test", "$db": "test"},
+            False,
+            id='no explain listIndexes',
+        ),
     ],
 )
 def test_should_explain_operation(namespace, op, command, should_explain):