Prevent exception when panel has multiple queries (#49368) (#49562)

This fixes the issues that when a panel has multiple queries this throws an exception if source is not part of the current frame

Co-authored-by: Ryan McKinley <ryantxu@gmail.com>
(cherry picked from commit eab806620c)

Co-authored-by: Ward Bekker <ward@wardbekker.com>

public/app/features/transformers/extractFields/extractFields.ts

@@ -41,7 +41,8 @@ function addExtractedFields(frame: DataFrame, options: ExtractFieldsOptions): Da
   }
   const source = findField(frame, options.source);
   if (!source) {
-    throw new Error('json field not found');
+    // this case can happen when there are multiple queries
+    return frame;
   }
 
   const ext = fieldExtractors.getIfExists(options.format ?? FieldExtractorID.Auto);