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/permission.go

@@ -167,6 +167,8 @@ var PermissionGetLogs *Permission
 var PermissionGetAnalytics *Permission
 var PermissionReadLicenseInformation *Permission
 var PermissionManageLicenseInformation *Permission
+var PermissionManagePublicChannelBanner *Permission
+var PermissionManagePrivateChannelBanner *Permission
 
 var PermissionSysconsoleReadAbout *Permission
 var PermissionSysconsoleWriteAbout *Permission
@@ -1283,6 +1285,20 @@ func initializePermissions() {
 		PermissionScopeChannel,
 	}
 
+	PermissionManagePublicChannelBanner = &Permission{
+		"manage_public_channel_banner",
+		"",
+		"",
+		PermissionScopeChannel,
+	}
+
+	PermissionManagePrivateChannelBanner = &Permission{
+		"manage_private_channel_banner",
+		"",
+		"",
+		PermissionScopeChannel,
+	}
+
 	PermissionReadOtherUsersTeams = &Permission{
 		"read_other_users_teams",
 		"authentication.permissions.read_other_users_teams.name",
@@ -2520,6 +2536,8 @@ func initializePermissions() {
 		PermissionEditBookmarkPrivateChannel,
 		PermissionDeleteBookmarkPrivateChannel,
 		PermissionOrderBookmarkPrivateChannel,
+		PermissionManagePublicChannelBanner,
+		PermissionManagePrivateChannelBanner,
 	}
 
 	GroupScopedPermissions := []*Permission{