Adjust language selector styling

[hjiangsu]

Pull Request Description

This PR is a follow up to some of the discussions from #1165. In particular:

• I've moved the LanguageSelector widget to its own shared file (to be used by both post and comment creation pages)
• Adjusted the styling of the language selector to match more closely to Lemmy UI

@micahmo @machinaeZER0 let me know your thoughts on the style change!

Issue Being Fixed

Issue Number: N/A

Screenshots / Recordings

Before	After

Checklist

• Did you update CHANGELOG.md?
• Did you use localized strings where applicable?
• Did you add semanticLabels where applicable for accessibility?

[micahmo]

I think it looks pretty slick! The only feedback I might have is to use a right-facing chevron. On the web, the down arrow implies a literal dropdown, but we're showing a modal. I think we use the right chevron in other places like the account/community selector to imply a modal popup of some sort. Thoughts?

[machinaeZER0]

I stylistically prefer the down one, but I agree that since it won't actually be a drop-down in our case that it makes less sense here. Either way I think this is great!

Side question: If the language name is long enough/the font size is big enough, does it interact weirdly with the NSFW toggle?

[micahmo]

One more tiny note: is it possible for the inkwell to only be as wide as the text? Right now it takes up the entire available width.

[hjiangsu]

The only feedback I might have is to use a right-facing chevron.

Done!

If the language name is long enough/the font size is big enough, does it interact weirdly with the NSFW toggle?

It seems like it wraps around the language:

is it possible for the inkwell to only be as wide as the text?

Done!