Rebuild channel index (#26080)

* WIP

* Added rebuild channels index functionality

* Added rough logic to send message to all sysadmins

* WIP

* WIP

* WIP

* Cleanup

* i18n fix

* reading through all pages of system admins

* Fixed webapp style

* i18n fix

* Added help text

* i18n fix

* i18n update

* Updated system console button action

* Updated snapshots

* some cleanup

* Updated snapshot

* Update server/channels/app/server.go

Co-authored-by: Daniel Espino García <larkox@gmail.com>

* fixed typo

* Refactoring to improve readibility

* moved index check to API later during config update

* Added some docs

* Updated get system bot

---------

Co-authored-by: Daniel Espino García <larkox@gmail.com>

server/channels/app/searchengine.go

@@ -36,18 +36,21 @@ func (a *App) SetSearchEngine(se *searchengine.Broker) {
 	a.ch.srv.platform.SearchEngine = se
 }
 
-func (a *App) PurgeElasticsearchIndexes(c request.CTX) *model.AppError {
+func (a *App) PurgeElasticsearchIndexes(c request.CTX, indexes []string) *model.AppError {
 	engine := a.SearchEngine().ElasticsearchEngine
 	if engine == nil {
 		err := model.NewAppError("PurgeElasticsearchIndexes", "ent.elasticsearch.test_config.license.error", nil, "", http.StatusNotImplemented)
 		return err
 	}
 
-	if err := engine.PurgeIndexes(c); err != nil {
-		return err
+	var appErr *model.AppError
+	if len(indexes) > 0 {
+		appErr = engine.PurgeIndexList(c, indexes)
+	} else {
+		appErr = engine.PurgeIndexes(c)
 	}
 
-	return nil
+	return appErr
 }
 
 func (a *App) PurgeBleveIndexes(c request.CTX) *model.AppError {