fix: use model name for file retrieval when not connected to the primary DB.

[OdenTakashi]

When the same table name exists in different databases, attempting to retrieve fixture and factory files references them by the table name. As a result, in addition to the fixtures and factories of models connected to the secondary database, related files from the primary database are also retrieved.

Therefore, this commit modifies the behavior so that for models connected to the secondary database, related files are retrieved based on the model name instead of the table name.

fixes #206