[release-20.0] Fix vttablet not being marked as not serving when MySQL stalls (#17883)#18452

timvaillancourt merged 1 commit intorelease-20.0vitessio/vitess:release-20.0from

backport-17883-to-release-20.0vitessio/vitess:backport-17883-to-release-20.0Copy head branch name to clipboard