MM-23935 extend session expiry on user activity (#14275)

* MM-23935  extend session expiry on user activity

- if user types anything before a session expires the session will be extended to now + session length

- ensures new session expiries are not written to DB too frequently

- new session store func for updating session ExpiresAt

- session length defaults for mobile and web/ldap changed from 180 days to 30 days

store/timer_layer.go

@@ -5291,6 +5291,22 @@ func (s *TimerLayerSessionStore) UpdateDeviceId(id string, deviceId string, expi
 	return resultVar0, resultVar1
 }
 
+func (s *TimerLayerSessionStore) UpdateExpiresAt(sessionId string, time int64) *model.AppError {
+	start := timemodule.Now()
+
+	resultVar0 := s.SessionStore.UpdateExpiresAt(sessionId, time)
+
+	elapsed := float64(timemodule.Since(start)) / float64(timemodule.Second)
+	if s.Root.Metrics != nil {
+		success := "false"
+		if resultVar0 == nil {
+			success = "true"
+		}
+		s.Root.Metrics.ObserveStoreMethodDuration("SessionStore.UpdateExpiresAt", success, elapsed)
+	}
+	return resultVar0
+}
+
 func (s *TimerLayerSessionStore) UpdateLastActivityAt(sessionId string, time int64) *model.AppError {
 	start := timemodule.Now()