[MM-58492] Remove subsequent check for team permissions on open channels (#27827)

* [MM-58492] Remove subsequent check for team permissions on open channels

* Removed extra check for open channel for webhooks as well

---------

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

server/channels/api4/post.go

@@ -572,9 +572,7 @@ func getPostsByIds(c *Context, w http.ResponseWriter, r *http.Request) {
 		}
 
 		if !c.App.SessionHasPermissionToReadChannel(c.AppContext, *c.AppContext.Session(), channel) {
-			if channel.Type != model.ChannelTypeOpen || (channel.Type == model.ChannelTypeOpen && !c.App.SessionHasPermissionToTeam(*c.AppContext.Session(), channel.TeamId, model.PermissionReadPublicChannel)) {
-				continue
-			}
+			continue
 		}
 
 		post = c.App.PreparePostForClient(c.AppContext, post, false, false, true)

server/channels/api4/webhook.go

@@ -51,7 +51,7 @@ func createIncomingHook(c *Context, w http.ResponseWriter, r *http.Request) {
 		return
 	}
 
-	if channel.Type != model.ChannelTypeOpen && !c.App.SessionHasPermissionToReadChannel(c.AppContext, *c.AppContext.Session(), channel) {
+	if !c.App.SessionHasPermissionToReadChannel(c.AppContext, *c.AppContext.Session(), channel) {
 		c.LogAudit("fail - bad channel permissions")
 		c.SetPermissionError(model.PermissionReadChannelContent)
 		return