Add non-github switch to show non-native GitHub emoji's

[rickstaa]

Is your feature request related to a problem? Please describe.

As explained by @SleepyCatten in https://github.com/rickstaa/github-emoji-picker/issues/202, users might want a way to see emojis which are not yet supported by GitHub and, therefore, don't have a shortcode (see this API endpoint for the supported emojis).

Describe the solution you'd like

Since GitHub does support unicode emojis we could add a non-github switch users can use also to be able to pick these non-native emojis and get the unicode copied to their clipboard instead.

Describe alternatives you've considered

Users can simply use https://missiveapp.com/open/emoji-mart instead. This however does not contain shortcodes for the emojis which GitHub does support.

Additional context

No response