MM-54778 Fix mark as unread on GMs (#24880)

* Fix mark as unread on GMs

* Don't count own messages in gms when marking as unread

* Change argument name

* Rename userId

---------

Co-authored-by: Mattermost Build <build@mattermost.com>

server/channels/store/timerlayer/timerlayer.go

@@ -731,10 +731,10 @@ func (s *TimerLayerChannelStore) ClearSidebarOnTeamLeave(userID string, teamID s
 	return err
 }
 
-func (s *TimerLayerChannelStore) CountPostsAfter(channelID string, timestamp int64, userID string) (int, int, error) {
+func (s *TimerLayerChannelStore) CountPostsAfter(channelID string, timestamp int64, excludedUserID string) (int, int, error) {
 	start := time.Now()
 
-	result, resultVar1, err := s.ChannelStore.CountPostsAfter(channelID, timestamp, userID)
+	result, resultVar1, err := s.ChannelStore.CountPostsAfter(channelID, timestamp, excludedUserID)
 
 	elapsed := float64(time.Since(start)) / float64(time.Second)
 	if s.Root.Metrics != nil {
@@ -747,10 +747,10 @@ func (s *TimerLayerChannelStore) CountPostsAfter(channelID string, timestamp int
 	return result, resultVar1, err
 }
 
-func (s *TimerLayerChannelStore) CountUrgentPostsAfter(channelID string, timestamp int64, userID string) (int, error) {
+func (s *TimerLayerChannelStore) CountUrgentPostsAfter(channelID string, timestamp int64, excludedUserID string) (int, error) {
 	start := time.Now()
 
-	result, err := s.ChannelStore.CountUrgentPostsAfter(channelID, timestamp, userID)
+	result, err := s.ChannelStore.CountUrgentPostsAfter(channelID, timestamp, excludedUserID)
 
 	elapsed := float64(time.Since(start)) / float64(time.Second)
 	if s.Root.Metrics != nil {