added check for 'error' property in responses returned from SiCKRAGE API when accessing series provider endpoints
added check inside `run` method in `ShowTaskForceRemove` class of value returned by `find_show`, if NoneType then exit method by returning NoneType
refactored series provider ID enum to use value as slug

added code to migrate series provider default language from 2-code to 3-code

fixed "string indices must be integers" when attempting to retrieve series provider season images
fixed "cannot serialize (type int)" when attempting to write series metadata nfo

switched anonymous referrer to anonym.to
fixed local variable 'refresh_token' referenced before assignment in cache offline token migration