Avoid a reflow when setting caret position on an empty composer (#8348)
Avoid a reflow when setting caret position on an empty composer (#8348)

This saves an extra ~12 ms on each room switch, because we can.
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