Revert "[MM-8497] Ability to set Do Not Disturb for a specified period of time (#16067)" (#17657)

This reverts commit 77d42568f9.

app/server.go

@@ -205,9 +205,6 @@ type Server struct {
 	featureFlagStop              chan struct{}
 	featureFlagStopped           chan struct{}
 	featureFlagSynchronizerMutex sync.Mutex
-
-	dndnTaskMut sync.Mutex
-	dndTask     *model.ScheduledTask
 }
 
 func NewServer(options ...Option) (*Server, error) {
@@ -668,7 +665,6 @@ func NewServer(options ...Option) (*Server, error) {
 			s.runLicenseExpirationCheckJob()
 			runCheckAdminSupportStatusJob(fakeApp, c)
 			runCheckWarnMetricStatusJob(fakeApp, c)
-			runDNDStatusExpireJob(fakeApp)
 		})
 		s.runJobs()
 	}
@@ -1047,12 +1043,6 @@ func (s *Server) Shutdown() {
 		mlog.Warn("Error flushing logs", mlog.Err(err))
 	}
 
-	s.dndnTaskMut.Lock()
-	if s.dndTask != nil {
-		s.dndTask.Cancel()
-	}
-	s.dndnTaskMut.Unlock()
-
 	mlog.Info("Server stopped")
 
 	// this should just write the "server stopped" record, the rest are already flushed.
@@ -2286,26 +2276,3 @@ func (s *Server) ReadFile(path string) ([]byte, *model.AppError) {
 // 	}
 // 	return result, nil
 // }
-
-func runDNDStatusExpireJob(a *App) {
-	if a.IsLeader() {
-		a.srv.dndnTaskMut.Lock()
-		a.srv.dndTask = model.CreateRecurringTaskFromNextIntervalTime("Unset DND Statuses", a.UpdateDNDStatusOfUsers, 5*time.Minute)
-		a.srv.dndnTaskMut.Unlock()
-	}
-	a.srv.AddClusterLeaderChangedListener(func() {
-		mlog.Info("Cluster leader changed. Determining if unset DNS status task should be running", mlog.Bool("isLeader", a.IsLeader()))
-		if a.IsLeader() {
-			a.srv.dndnTaskMut.Lock()
-			a.srv.dndTask = model.CreateRecurringTaskFromNextIntervalTime("Unset DND Statuses", a.UpdateDNDStatusOfUsers, 5*time.Minute)
-			a.srv.dndnTaskMut.Unlock()
-		} else {
-			a.srv.dndnTaskMut.Lock()
-			if a.srv.dndTask != nil {
-				a.srv.dndTask.Cancel()
-				a.srv.dndTask = nil
-			}
-			a.srv.dndnTaskMut.Unlock()
-		}
-	})
-}