[MM-16330] Migrate "Channel.GetForPost" to Sync by default (#11199)

app/authorization.go

@@ -75,8 +75,7 @@ func (a *App) SessionHasPermissionToChannelByPost(session model.Session, postId
 		}
 	}
 
-	if result := <-a.Srv.Store.Channel().GetForPost(postId); result.Err == nil {
-		channel := result.Data.(*model.Channel)
+	if channel, err := a.Srv.Store.Channel().GetForPost(postId); err == nil {
 		if channel.TeamId != "" {
 			return a.SessionHasPermissionToTeam(session, channel.TeamId, permission)
 		}
@@ -175,8 +174,7 @@ func (a *App) HasPermissionToChannelByPost(askingUserId string, postId string, p
 		}
 	}
 
-	if result := <-a.Srv.Store.Channel().GetForPost(postId); result.Err == nil {
-		channel := result.Data.(*model.Channel)
+	if channel, err := a.Srv.Store.Channel().GetForPost(postId); err == nil {
 		return a.HasPermissionToTeam(askingUserId, channel.TeamId, permission)
 	}