Start sync

[bmarty]

Type of change

• Feature
• Bugfix
• Technical
• Other :

Content

Ensure sync thread is started when the app recover from a crash or from a process killed by the system.

Motivation and context

See message coming when using the app.
Closes #8010

Also fixing a rendering issue when messages fail to be sent:

• Adding a /crash command, only auto-completed (and active) when in developer mode to crash the app and provokate a recovery.

Screenshots / GIFs

Before	After

Tests

• Step 1
• Step 2
• Step ...

Tested devices

• Physical
• Emulator
• OS version(s):

Checklist

• Changes has been tested on an Android device or Android emulator with API 21
• UI change has been tested on both light and dark themes
• Accessibility has been taken into account. See https://github.com/vector-im/element-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/vector-im/element-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
• If you have modified the screen flow, or added new screens to the application, you have updated the test UiAllScreensSanityTest.allScreensTest()

[sonarqubecloud]

SonarCloud Quality Gate failed.   

0 Bugs
0 Vulnerabilities
0 Security Hotspots
0 Code Smells

66.7% Coverage
0.0% Duplication

[Florian14]

lgtm

[Florian14]

Is this comment really useful? Not an issue at all

[bmarty]

Ah, yes, a bit useless. I added the comment when the use case had another name. Could be removed now (but I will not trigger the CI for that).