Don't crash if a keyshare request is removed
Don't crash if a keyshare request is removed

...during the time the dialog is displayed.

Fixes https://github.com/vector-im/riot-web/issues/11745 (hopefully)

matrix-org/matrix-react-sdk,matrix-org/matrix-react-sdk,matrix-org/matrix-react-sdk,matrix-org/matrix-react-sdk,matrix-org/matrix-react-sdk,matrix-org/matrix-react-sdk