docs(core): Add changelog for supabase PostgREST nullish response fix (#5939)

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

Author: antonis

CHANGELOG.md

@@ -16,6 +16,7 @@
 
 ### Fixes
 
+- Fix crash caused by nullish response in supabase PostgREST handler ([#5938](https://github.com/getsentry/sentry-react-native/pull/5938))
 - Fix iOS crash (EXC_BAD_ACCESS) in time-to-initial-display when navigating between screens ([#5887](https://github.com/getsentry/sentry-react-native/pull/5887))
 
 ### Dependencies