Stop using original_event field

[bmarty]

Homeservers will not return RelationsResponse.original_event in the future.

Type of change

• Feature
• Bugfix
• Technical
• Other :

Content

See #7275: stop using original_event field.
We will move to v1 endpoint later (and probably more globally).

Motivation and context

Comply with spec.

Screenshots / GIFs

Tests

• Smoke tests

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()

[bmarty]

(we have to do that outside of the Realm transaction below)

[sonarqubecloud]

SonarCloud Quality Gate failed.   

0 Bugs
0 Vulnerabilities
0 Security Hotspots
0 Code Smells

0.0% Coverage
0.0% Duplication