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

api4/channel.go

@@ -1073,7 +1073,7 @@ func addChannelMember(c *Context, w http.ResponseWriter, r *http.Request) {
 		return
 	}
 
-	cm, err := c.App.AddChannelMember(member.UserId, channel, c.Session.UserId, postRootId)
+	cm, err := c.App.AddChannelMember(member.UserId, channel, c.Session.UserId, postRootId, !c.Session.IsMobileApp())
 	if err != nil {
 		c.Err = err
 		return

api4/post.go

@@ -58,7 +58,7 @@ func createPost(c *Context, w http.ResponseWriter, r *http.Request) {
 		post.CreateAt = 0
 	}
 
-	rp, err := c.App.CreatePostAsUser(c.App.PostWithProxyRemovedFromImageURLs(post))
+	rp, err := c.App.CreatePostAsUser(c.App.PostWithProxyRemovedFromImageURLs(post), !c.Session.IsMobileApp())
 	if err != nil {
 		c.Err = err
 		return