docs(feedback): Update docs for onSubmitSuccess to include eventID (#14310)

Also added a note for how to use `eventID` to link back to sentry.io

<img width="815" alt="SCR-20250709-ntqc"
src="https://github.com/user-attachments/assets/55bfa501-416d-4a52-a5fc-1baa655bbf2c"
/>


Related to getsentry/sentry-javascript#16835
Related to getsentry/sentry-javascript#16836

---------

Co-authored-by: Michelle Zhang <[email protected]>

Author: 2 people

docs/platforms/javascript/common/user-feedback/configuration/index.mdx

@@ -239,13 +239,17 @@ Sentry.init({
     Sentry.feedbackIntegration({
       onFormOpen: () => {},
       onFormClose: () => {},
-      onSubmitSuccess: (data: FeedbackFormData) => {},
+      onSubmitSuccess: (data: FeedbackFormData, eventID: string) => {},
       onSubmitError: (error: Error) => {},
     }),
   ],
 });
 ```
 
+You can link directly to a saved feedback item by implementing the `onSubmitSuccess` callback. The URL you need to construct is `https://\$\{orgSlug}.sentry.io/issues/feedback/?projectSlug=\$\{projectSlug}&eventId=\$\{eventId}`.
+
+*Note:* In v9 and below of the SDK, the signature of `onSubmitSuccess` was `(data: FeedbackFormData) => {}`.
+
 ### Bring Your Own Button
 
 You can use your own button instead of the default injected button to trigger the form being displayed, by calling `feedback.attachTo()` to have the SDK attach a click listener to your button. You can also supply the same customization options that the constructor accepts (for example, for text labels and colors).