Use legacy call membership if anyone else is

[AndrewFerr]

Signed-off-by: Andrew Ferrazzutti andrewf@element.io

Checklist

• [x] Tests written for new code (and old code if feasible).
• [x] New or updated public/exported symbols have accurate TSDoc documentation.
• [x] Linter and other CI checks pass.
• [x] Sign-off given on the changes (see CONTRIBUTING.md).

[toger5]

Can you also add this change:

[toger5]

Thanks for porting this into its own PR and making it better!