fix(night mode) Save night mode in cookies

[vekkele]

Summary

For now night-mode saving doesn't work properly for anon user since we have server-side check for night mode in user settings and setting body class after that. It leads to desync between useUiCtx state and visual (body class) page appearance.

Another problem is saving in local storage leads to white page blink

Fixes:

1. Save night mode setting in cookies instead of local storage to ensure proper retrieving user preference on server (during handle hook).
2. Check for user preferences in single place (handle hook) instead of both hook and useUiCtx
3. Preference check now checking for currentUser settings and cookies. I removed checking for body class since there is no document on the server
4. Fix copy button border in ShareDialog

Notion card

https://www.notion.so/santiment/Fix-night-mode-bugs-2d12a82d1361804e8fa6c61d0dc685d6?source=copy_link