Don't attempt to send expand/collapse events for disabled TreeGrid. (#11823)

Don't attempt to send expand/collapse events for disabled TreeGrid. (#11823)

The attempt gets blocked later down the line in any case and never
reaches the server, but sending it messes up TreeGrid's internal state.
It gets stuck waiting for the resolution of the blocked call that can
then only be resolved by server-side sending its own expand/collapse
request programmatically. Until that happens no further expand/collapse
attempts will get sent to server even after the TreeGrid has been
enabled again.

Tree is also affected as it is built upon TreeGrid.

Fixes #11822