Refactor remote Config fetching request to be asynchronous

[SleepySquash]

Synopsis

Offline mode DOESN'T work currently. This is caused by Config.init() method fetching the remote config in a await fashion. This causes application to await the remote request to be done and fetched. However, when there's no Internet connection or the request hangs up, then the application doesn't launch at all.

Solution

This PR fixes this issue by making the request non-awaitable.

Checklist

• Created PR:
  • In draft mode
  • Name contains issue reference
  • Has type and k:: labels applied
• Before review:
  • Documentation is updated (if required)
  • Tests are updated (if required)
  • Changes conform code style
  • CHANGELOG entry is added (if required)
  • FCM (final commit message) is posted or updated
  • Draft mode is removed
• Review is completed and changes are approved
  • FCM (final commit message) is approved
• Before merge:
  • Milestone is set
  • PR's name and description are correct and up-to-date
  • All temporary labels are removed

[SleepySquash]

FCM

Refactor remote `Config` fetching request to be asynchronous (#1211)