chore: update RNTester example link in PanResponder comment (#30051)

Summary:
This PR fixes a small leftover after the RNTester migration to the monorepo package - an invalid link in the `PanResponder` comment.

Refs:
* https://github.com/facebook/react-native/issues/29567
* facebook/react-native-website#2177 (the similar correction was a part of merged PR in the RN docs)

## Changelog

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[Internal][Fixed] PanResponder: correct example link in comment

Pull Request resolved: https://github.com/facebook/react-native/pull/30051

Test Plan: N/A

Reviewed By: fkgozali

Differential Revision: D24025065

Pulled By: hramos

fbshipit-source-id: 190486e458fb8e83a35fa2d3c62f4483f3a4334d

Libraries/Interaction/PanResponder.js

@@ -121,7 +121,7 @@ const currentCentroidY = TouchHistoryMath.currentCentroidY;
  * ### Working Example
  *
  * To see it in action, try the
- * [PanResponder example in RNTester](https://github.com/facebook/react-native/blob/master/RNTester/js/PanResponderExample.js)
+ * [PanResponder example in RNTester](https://github.com/facebook/react-native/blob/master/packages/rn-tester/js/examples/PanResponder/PanResponderExample.js)
  */
 
 export type GestureState = {|