Handle errors in sending messages during commissioning. (#30068)

The commissioning state machine, when handling a state, needs to either queue up
an async process that will eventually push the state machine along or needs to
fail out and stop the commissioning process.  We had a number of state handlers
that could fail to do both if the attempt to send the message failed, which
would leave the commissioner in a stuck state where it thought it was waiting
for the async work, while the async work was not queued.

This change adds the relevant error checks to ensure we never wait for work that
has not started.

Fixes #30041

Author: bzbarsky-apple