Fix user id type mismatch in api endpoints — a Cursor (Anysphere) flight by voicebootix

From the pull request description

Remove redundant user ID conversion to fix type mismatch in profile and credits endpoints. The `get_user_id_as_int()` function already returns an integer, but its result was erroneously passed to `convert_user_id_to_int()`, which expects a string, leading to runtime type errors.