SSE: Add constant for data source name (#48443)

* add property for expressions datasource name

* remove console log

packages/grafana-runtime/src/utils/DataSourceWithBackend.ts

@@ -34,6 +34,7 @@ import { BackendDataSourceResponse, toDataQueryResponse } from './queryResponse'
 export const ExpressionDatasourceRef = Object.freeze({
   type: '__expr__',
   uid: '__expr__',
+  name: 'Expression',
 });
 
 /**

public/app/features/expressions/ExpressionDatasource.ts

@@ -69,7 +69,7 @@ export const ExpressionDatasourceUID = '-100';
 export const instanceSettings: DataSourceInstanceSettings = {
   id: -100,
   uid: ExpressionDatasourceUID,
-  name: ExpressionDatasourceRef.type,
+  name: ExpressionDatasourceRef.name,
   type: ExpressionDatasourceRef.type,
   access: 'proxy',
   meta: {