by fixing the cause rather than the symptom: this upgrades the code to use the new, recommended JSX transform mode of React 17+, which no longer requires you to import React manually just to write JSX.
See comment, although this is quite hack - I'm torn on whether this
is worth it for the bugfix. Upgrading react-aria doesn't fix it either
(and also breaks everything in React strict mode).
Fixes https://github.com/vector-im/element-call/issues/762
