Remove the unobservable showMuteResultModal reset in
ProfilePage._broadcastMute: the flag is set true unconditionally after the
awaited broadcast, so no observer can read the reset value. Add unit coverage
for getMuteResultError's empty-string contract when there is no result and
when a failure carries no message. Record the tool-written mutation and
acceptance-mutation manifests.
Mutation: 31 killed, 0 survived, 0 uncovered (profile-page.js). CRAP <= 4.
DRY clean. Soft Gherkin: 5 intrinsic case-equivalents.
By architect.
Chris Troutner