Refactor test_CredentialsManager to consolidate imports

Author: arash77

test/unit/app/managers/test_CredentialsManager.py

@@ -3,18 +3,18 @@
     Tuple,
 )
 
-from galaxy.managers.credentials import CredentialsManager
+from galaxy.managers.credentials import (
+    CredentialsManager,
+    CredentialsModelList,
+)
 from galaxy.model import (
     CredentialsGroup,
     Secret,
     User,
     UserCredentials,
     Variable,
 )
-from galaxy.schema.credentials import (
-    CredentialsModelList,
-    SOURCE_TYPE,
-)
+from galaxy.schema.credentials import SOURCE_TYPE
 from .base import BaseTestCase