Fix extra negotiate message in Firefox
Fix extra negotiate message in Firefox

Hopefully explained by the comments: Firefox sees that it's been
put on hold and tries to negotiate itself off hold again.

Fixes https://github.com/vector-im/element-web/issues/16190

matrix-org/matrix-js-sdk,matrix-org/matrix-js-sdk,matrix-org/matrix-js-sdk,matrix-org/matrix-js-sdk