fix(NcMentionBubble): inject component styles in NcRichContenteditable

[Antreesy]

☑️ Resolves

• Fix NcRichContenteditable: @mention item is not rendered properly in other apps #4901
  • 👎 genSelectTemplate returns a HTML template of NcMentionBubble component with scoped style attribute data-v-123, but these styles are not included in the bundled chunk for some reason
  • 👎 Because of that, NcRichContenteditable renders mention template as expected, but without applied styles
  • 👍 PR extracts NcMentionBubble styles to a mixin, so it could be included in every needed component to its scoped styles like this:

@import '../../assets/NcMentionBubble';
:deep(.mention-bubble) {
	@include mention-bubble;
}

Drawback: because NcMentionBubble is still imported by richeditor mixin, styles in the compiled JS file are duplicated, but it's about 7 style rules, so lesser evil 👿

Tested with Talk chat, Files comments, and should be applicable for other apps

🖼️ Screenshots

🏚️ Before	🏡 After

For Files, name/label is not provided on server-side -> unrelated to this PR

🏁 Checklist

• ⛑️ Tests are included or are not applicable
• 📘 Component documentation has been extended, updated or is not applicable

[susnux]

This is a not that nice work around, the real but seems to be the way we use it + a bug in vite. As vite removes the chunk that imports the css :/
I am currently digging into vite source

[Antreesy]

I am currently digging into vite source

https://vitejs.dev/config/build-options.html#build-csscodesplit

Could it be related?

[susnux]

No the problem is vite removes chunks that only import css in the generateBundle hook, but we currently inject css only in the renderChunk hook which is called before.
I do not think it is a bug but a decision -> if you remove the chunks in renderChunk you would need to check every chunk twice.

The solution would be to fix the css plugin to also do the import in generateBundle but this might lead to duplicated code, but I will try.

[Antreesy]

Superseded by nextcloud-libraries/nextcloud-vite-config#112