Support for stable MSC3882 get_login_token

[hughns]

Type of change

• Feature
• Bugfix
• Technical
• Other :

Content

Motivation and context

This adds support for the stable capability negotiation for the get login token endpoint used by Sign in with QR.

These PR leaves support for the unstable release 0 in place. It is my intention that the support for the unstable version would be removed in a future release once the stable support has made it into Synapse via matrix-org/synapse#15388.

Screenshots / GIFs

Tests

• Step 1
• Step 2
• Step ...

Tested devices

• Physical
• Emulator
• OS version(s): SDK 33

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()

Signed-off-by: Hugh Nimmo-Smith hughns@element.io

[sonarqubecloud]

SonarCloud Quality Gate failed.   

0 Bugs
0 Vulnerabilities
0 Security Hotspots
2 Code Smells

0.0% Coverage
0.0% Duplication

[bmarty]

LGTM, thanks! Feel free to merge the PR.