MM-7188: Cleaning push notification on every read, not only on channel switch (#9348)

* MM-7188: Cleaning push notification on every read, not only on channel switch

* Removed unnecesary goroutine

* Fixing tests

* Applying suggestion from PR

store/store.go

@@ -265,6 +265,7 @@ type UserStore interface {
 	AnalyticsActiveCount(time int64) StoreChannel
 	GetUnreadCount(userId string) StoreChannel
 	GetUnreadCountForChannel(userId string, channelId string) StoreChannel
+	GetAnyUnreadPostCountForChannel(userId string, channelId string) StoreChannel
 	GetRecentlyActiveUsersForTeam(teamId string, offset, limit int) StoreChannel
 	GetNewUsersForTeam(teamId string, offset, limit int) StoreChannel
 	Search(teamId string, term string, options map[string]bool) StoreChannel