Fix crash when signing out.

[bmarty]

At this point, we do not want the sync to start, the DB is already deleted.

Type of change

• Feature
• Bugfix
• Technical
• Other :

Content

Do not start the SyncThread if the user want to sign out.
Related to #6884

Motivation and context

Fix crash when signing out.

Screenshots / GIFs

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()

[ouchadam]

makes sense 👍

[sonarqubecloud]

Kudos, SonarCloud Quality Gate passed!   

0 Bugs
0 Vulnerabilities
0 Security Hotspots
0 Code Smells

0.0% Coverage
0.0% Duplication

[bmarty]

A test is failing (twice), first time I see that, so maybe related to the change in this PR :/

org.matrix.android.sdk.internal.crypto.E2eeSanityTests > testBasicBackupImport[test(AVD) - 9] FAILED
java.lang.IllegalStateException: This Realm instance has already been closed, making it unusable.

[bmarty]

#6917 also suffers from the same test error. We will investigate later.