Let Expo/Webpack handle CSS assets (#3942)

* chore: handle built css assets

* chore: let prettier handle css code

* refactor: let webpack build css assets

* chore: prettier on bskyembed

* chore: touch empty.txt on css directory

* chore: do the same to the workflow

src/App.web.tsx

@@ -1,5 +1,6 @@
 import 'lib/sentry' // must be near top
 import 'view/icons'
+import './style.css'
 
 import React, {useEffect, useState} from 'react'
 import {KeyboardProvider} from 'react-native-keyboard-controller'