states.postgres_extension: Fixed unit test patching (and renamed to PostgresExtensionTestCase for future tests)
Added unit tests for postgres_user.present
Fixed state postgres_user always updating on test=True
Fixed postgres_group.present always updating on test=True
Fixed MagicMock import in postgres_test
Merge pull request #13074 from thunderk/fix_postgres_state_test

Fix postgres states with test=True (#12968)