Improve UX on notification setting changes

[bmarty]

Type of change

• Feature
• Bugfix
• Technical
• Other :

Content

In the demo below:

• 2 first screens: ensure that the toggle is updated at the same time that the Progress dialog is hidden. In this case, the process is taking time so there is no need to ensure a minimal process duration.
• last screen (room notification setting) Ensure that the progress dialog is displayed at least 500ms to avoid flickering.

Motivation and context

Closes #1647

Screenshots / GIFs

Tests

• Play with the notification settings.

Tested devices

• Physical
• Emulator
• OS version(s):

Checklist

• Changes have been tested on an Android device or Android emulator with API 23
• UI change has been tested on both light and dark themes
• Accessibility has been taken into account. See https://github.com/element-hq/element-x-android/blob/develop/CONTRIBUTING.md#accessibility
• Pull request is based on the develop branch
• Pull request includes a new file under ./changelog.d. See https://github.com/element-hq/element-x-android/blob/develop/CONTRIBUTING.md#changelog
• Pull request includes screenshots or videos if containing UI changes
• Pull request includes a sign off
• You've made a self review of your PR

[github-actions]

📱 Scan the QR code below to install the build (arm64 only) for this PR.

If you can't scan the QR code you can install the build via this link: https://i.diawi.com/VuMzEo

[codecov]

Codecov Report

Attention: Patch coverage is 91.30435% with 2 lines in your changes missing coverage. Please review.

Project coverage is 75.79%. Comparing base (55a1ac4) to head (0233e86).
Report is 1 commits behind head on develop.

Files	Patch %	Lines
...tificationsettings/RoomNotificationSettingsView.kt	0.00%	1 Missing ⚠️
...ettings/UserDefinedRoomNotificationSettingsView.kt	0.00%	1 Missing ⚠️

Additional details and impacted files

@@           Coverage Diff            @@
##           develop    #3022   +/-   ##
========================================
  Coverage    75.78%   75.79%           
========================================
  Files         1611     1611           
  Lines        38101    38105    +4     
  Branches      7362     7364    +2     
========================================
+ Hits         28875    28880    +5     
  Misses        5373     5373           
+ Partials      3853     3852    -1     

☔ View full report in Codecov by Sentry.
📢 Have feedback on the report? Share it here.

[sonarqubecloud]

Quality Gate passed

Issues
0 New issues
0 Accepted issues

Measures
0 Security Hotspots
0.0% Coverage on New Code
0.0% Duplication on New Code

See analysis details on SonarCloud

[jmartinesp]

LGTM, thanks!