[MM-23019] Create use_group_mentions permission and migrate existing roles (#13987)

* MM-22962 Create use_group_mentions permission and give to all non guest roles that can create post

* Add use_group_mentions to team admin role for test

* Trigger CI

* MM-22962 Remove old migration keys

model/migration.go

@@ -16,4 +16,5 @@ const (
 	MIGRATION_KEY_VIEW_MEMBERS_NEW_PERMISSION                 = "view_members_new_permission"
 	MIGRATION_KEY_ADD_MANAGE_GUESTS_PERMISSIONS               = "add_manage_guests_permissions"
 	MIGRATION_KEY_CHANNEL_MODERATIONS_PERMISSIONS             = "channel_moderations_permissions"
+	MIGRATION_KEY_ADD_USE_GROUP_MENTIONS_PERMISSION           = "add_use_group_mentions_permission"
 )

model/permission.go

@@ -91,6 +91,7 @@ var PERMISSION_INVITE_GUEST *Permission
 var PERMISSION_PROMOTE_GUEST *Permission
 var PERMISSION_DEMOTE_TO_GUEST *Permission
 var PERMISSION_USE_CHANNEL_MENTIONS *Permission
+var PERMISSION_USE_GROUP_MENTIONS *Permission
 
 // General permission that encompasses all system admin functions
 // in the future this could be broken up to allow access to some
@@ -567,6 +568,13 @@ func initializePermissions() {
 		PERMISSION_SCOPE_CHANNEL,
 	}
 
+	PERMISSION_USE_GROUP_MENTIONS = &Permission{
+		"use_group_mentions",
+		"authentication.permissions.use_group_mentions.name",
+		"authentication.permissions.use_group_mentions.description",
+		PERMISSION_SCOPE_CHANNEL,
+	}
+
 	ALL_PERMISSIONS = []*Permission{
 		PERMISSION_INVITE_USER,
 		PERMISSION_ADD_USER_TO_TEAM,
@@ -643,6 +651,7 @@ func initializePermissions() {
 		PERMISSION_PROMOTE_GUEST,
 		PERMISSION_DEMOTE_TO_GUEST,
 		PERMISSION_USE_CHANNEL_MENTIONS,
+		PERMISSION_USE_GROUP_MENTIONS,
 	}
 
 	CHANNEL_MODERATED_PERMISSIONS = []string{