[release-21.0] Fix vttablet not being marked as not serving when MySQL stalls (#17883)#18453

timvaillancourt merged 1 commit intorelease-21.0vitessio/vitess:release-21.0from

backport-17883-to-release-21.0vitessio/vitess:backport-17883-to-release-21.0Copy head branch name to clipboard