Navigation test refactoring - improving structure for scenarios that don't support collections

Plus minor cleanup

Fixes #35707

Author: maumar

Diff for: test/EFCore.Cosmos.FunctionalTests/Query/Relationships/InProjection/JsonRelationshipsInProjectionNoTrackingQueryCosmosTest.cs

@@ -5,7 +5,7 @@
 
 namespace Microsoft.EntityFrameworkCore.Query.Relationships;
 
-public class JsonRelationshipsQueryCosmosFixture : JsonRelationshipsQueryFixtureBase
+public class OwnedJsonRelationshipsCosmosFixture : OwnedJsonRelationshipsFixtureBase
 {
     public TestSqlLoggerFactory TestSqlLoggerFactory
         => (TestSqlLoggerFactory)ListLoggerFactory;