Revert "MM-14845: Fix Update and Patch channel for private channels. (#10539)" (#10599)

This reverts commit 0bef611f7a.

api4/channel.go

@@ -120,12 +120,6 @@ func updateChannel(c *Context, w http.ResponseWriter, r *http.Request) {
 			return
 		}
 
-		// Since the `team_user` role can have PERMISSION_MANAGE_PRIVATE_CHANNEL_PROPERTIES out of the box, we must additionally check membership for private channels.
-		if _, memberErr := c.App.GetChannelMember(channel.Id, c.App.Session.UserId); memberErr != nil {
-			c.Err = model.NewAppError("updateChannel", "api.channel.patch_update_channel.forbidden.app_error", nil, "", http.StatusForbidden)
-			return
-		}
-
 	case model.CHANNEL_GROUP, model.CHANNEL_DIRECT:
 		// Modifying the header is not linked to any specific permission for group/dm channels, so just check for membership.
 		if _, err := c.App.GetChannelMember(channel.Id, c.App.Session.UserId); err != nil {
@@ -263,12 +257,6 @@ func patchChannel(c *Context, w http.ResponseWriter, r *http.Request) {
 			return
 		}
 
-		// Since the `team_user` role can have PERMISSION_MANAGE_PRIVATE_CHANNEL_PROPERTIES out of the box, we must additionally check membership for private channels.
-		if _, memberErr := c.App.GetChannelMember(c.Params.ChannelId, c.App.Session.UserId); memberErr != nil {
-			c.Err = model.NewAppError("patchChannel", "api.channel.patch_update_channel.forbidden.app_error", nil, "", http.StatusForbidden)
-			return
-		}
-
 	case model.CHANNEL_GROUP, model.CHANNEL_DIRECT:
 		// Modifying the header is not linked to any specific permission for group/dm channels, so just check for membership.
 		if _, err = c.App.GetChannelMember(c.Params.ChannelId, c.App.Session.UserId); err != nil {