docs(changelog): Add changelog for playground open-url in Expo

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

Author: antonis

CHANGELOG.md

@@ -10,6 +10,7 @@
 
 ### Features
 
+- Enable "Open Sentry" button in Playground for Expo apps ([#5947](https://github.com/getsentry/sentry-react-native/pull/5947))
 - Add `frames.delay` span data from native SDKs to app start, TTID/TTFD, and JS API spans ([#5907](https://github.com/getsentry/sentry-react-native/pull/5907))
 - Rename `FeedbackWidget` to `FeedbackForm` and `showFeedbackWidget` to `showFeedbackForm` ([#5931](https://github.com/getsentry/sentry-react-native/pull/5931))
   - The old names are deprecated but still work