Channel banner permissions (#30917)

* Fixed save state panel for channel banner

* Defined default background color

* Updated test

* WIP

* wip

* removed unused param

* Updated tests

* CI

* Fixed mmctl test

* Fixed TestDoAdvancedPermissionsMigration test

* Test update

* lint fix

* lint fix

---------

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

server/public/model/role.go

@@ -914,6 +914,8 @@ func MakeDefaultRoles() map[string]*Role {
 			PermissionEditBookmarkPrivateChannel.Id,
 			PermissionDeleteBookmarkPrivateChannel.Id,
 			PermissionOrderBookmarkPrivateChannel.Id,
+			PermissionManagePublicChannelBanner.Id,
+			PermissionManagePrivateChannelBanner.Id,
 		},
 		SchemeManaged: true,
 		BuiltIn:       true,
@@ -1000,6 +1002,8 @@ func MakeDefaultRoles() map[string]*Role {
 			PermissionEditBookmarkPrivateChannel.Id,
 			PermissionDeleteBookmarkPrivateChannel.Id,
 			PermissionOrderBookmarkPrivateChannel.Id,
+			PermissionManagePublicChannelBanner.Id,
+			PermissionManagePrivateChannelBanner.Id,
 		},
 		SchemeManaged: true,
 		BuiltIn:       true,