fix(datasource_srv): prevent infinite loop where default datasource is named default (#32949) (#32967)

(cherry picked from commit b0470c84a5)

Co-authored-by: Jack Westbrook <jack.westbrook@gmail.com>

public/app/features/plugins/datasource_srv.ts

@@ -97,7 +97,7 @@ export class DatasourceSrv implements DataSourceService {
     // Interpolation here is to support template variable in data source selection
     nameOrUid = this.templateSrv.replace(nameOrUid, scopedVars, variableInterpolation);
 
-    if (nameOrUid === 'default') {
+    if (nameOrUid === 'default' && this.defaultName !== 'default') {
       return this.get(this.defaultName);
     }