Support for experimental MSC4286 to not render external payment details

[hughns]

Implementation of MSC4286

Two parts to it:

• upgrade of matrix-rust-sdk so that the new span attribute is not stripped at that layer
• detect the new attribute and exclude the whole span from the rendering

Depends on matrix-org/matrix-rust-sdk#5101 which was in https://github.com/element-hq/matrix-rust-components-swift/releases/tag/25.05.27 and is landed via #4151

Before	After

In the above example the formatted_body of the event looks like this:

Thanks for subscribing!<span data-msc4286-external-payment-details> You can manage your subscription and view your payment history <a href="https://account.example.com/account/plan">here</a> at any time</span>

Pull Request Checklist

• I read the contributing guide.
• Pull request contains a changelog label.

UI changes have been tested with:

• iPhone and iPad simulators in portrait and landscape orientations.
• Dark mode enabled and disabled.
• Various sizes of dynamic type.
• Voiceover enabled.

[sonarqubecloud]

Quality Gate passed

Issues
0 New issues
0 Accepted issues

Measures
0 Security Hotspots
0.0% Coverage on New Code
0.0% Duplication on New Code

See analysis details on SonarQube Cloud

[pixlwave]

Code seems reasonable to me, thanks for the test.