[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

testlib/store.go

@@ -40,6 +40,7 @@ func GetMockStoreForSetupFunctions() *mocks.Store {
 	systemStore.On("GetByName", model.MIGRATION_KEY_VIEW_MEMBERS_NEW_PERMISSION).Return(&model.System{Name: model.MIGRATION_KEY_VIEW_MEMBERS_NEW_PERMISSION, Value: "true"}, nil)
 	systemStore.On("GetByName", model.MIGRATION_KEY_ADD_MANAGE_GUESTS_PERMISSIONS).Return(&model.System{Name: model.MIGRATION_KEY_ADD_MANAGE_GUESTS_PERMISSIONS, Value: "true"}, nil)
 	systemStore.On("GetByName", model.MIGRATION_KEY_CHANNEL_MODERATIONS_PERMISSIONS).Return(&model.System{Name: model.MIGRATION_KEY_CHANNEL_MODERATIONS_PERMISSIONS, Value: "true"}, nil)
+	systemStore.On("GetByName", model.MIGRATION_KEY_ADD_USE_GROUP_MENTIONS_PERMISSION).Return(&model.System{Name: model.MIGRATION_KEY_ADD_USE_GROUP_MENTIONS_PERMISSION, Value: "true"}, nil)
 	systemStore.On("Get").Return(make(model.StringMap), nil)
 	systemStore.On("Save", mock.AnythingOfType("*model.System")).Return(nil)