Fix crash on logout

[jmartinesp]

Type of change

• Feature
• Bugfix
• Technical
• Other :

Content

Replaces a call to client.setDelegate(null) with destroying the TashHandle returned by client.setDelegate now.

Motivation and context

Fix a crash that happened after a logout, where the delegate was called even after using client.setDelegate(null).

Tests

• Log in.
• Log out.
• Wait for 30s-1min.

It if doesn't crash (or if Maestro passes), it's fixed.

Tested devices

• Physical
• Emulator
• OS version(s): 11

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/vector-im/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/vector-im/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

[sonarcloud]

Kudos, SonarCloud Quality Gate passed!   

0 Bugs
0 Vulnerabilities
0 Security Hotspots
0 Code Smells

No Coverage information
No Duplication information

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Comparison is base (74ccdf8) 63.33% compared to head (7501440) 63.33%.

Additional details and impacted files

@@           Coverage Diff            @@
##           develop    #1749   +/-   ##
========================================
  Coverage    63.33%   63.33%           
========================================
  Files         1286     1286           
  Lines        33421    33421           
  Branches      6962     6962           
========================================
  Hits         21167    21167           
  Misses        9057     9057           
  Partials      3197     3197           

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

[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/VyES2U

[julioromano]

LGTM but see my remarks in the chat room.
This looks like a behavior change without an API change.
setDelegate has been returning a TaskHandle for months.
Perhaps best to discuss with the rust folks.

[jmartinesp]

We already discussed this, but I'm posting it here so we have some context of why it's needed. Taken from matrix-org/matrix-rust-sdk@ad5761b:

The fix here consists in having Client::set_delegate return a task handle that needs to be stashed by the FFI
users, and cancelled when the Client gets out of scope. This fixes the leak, by removing the last reference onto
the Client.