feat: Cleanup orphan extensions' settings

[yassine-sallemi]

Motivation

Unnecessary settings of orphan extensions are now deleted to avoid errors in frontend

Type of change:

• New feature (non-breaking change which adds functionality)

Checklist:

• I have performed a self-review of my own code
• I have commented my code, particularly in hard-to-understand areas

[marrouchi]

I suggest we make the service part of the setting module, let's call it CleanUpService.

Let's for now handle only channels and helpers.

[yassine-sallemi]

I think that making the new CleanupService part of the SettingModule will cause a problem, as it is loaded before the extensions are loaded, so it may delete some saved settings of some extensions, and therefore, you'll need to modify some settings upon each restart of the api server

[marrouchi]

@yassine-sallemi Then I suggest we add onModuleInit for each module (HelperService, ChannelService), so each one cleans up his own settings.