* refactor: checking `ALLOW_SOCIAL_REGISTRATION` with `isEnabled`
* feat: Add findUserByEmail function to UserService
This commit adds a new function, , to the module. This function retrieves a user document from the database based on the provided email. It returns the user document if found, otherwise it returns null. If there is a problem during user retrieval, an error is thrown.
* refactor: add socialLogin to remove repetitive code
