chore(sample): upload dSYMs to Crashlytics from internal TestFlight lane

Match the v10 branch — the internal TestFlight lane should upload dSYMs
to Firebase Crashlytics like distribute_to_testflight does, so symbolicated
crash reports are available for internal-tester builds.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

Author: xsahil03x

sample_app/ios/fastlane/Fastfile

@@ -133,6 +133,8 @@ platform :ios do
     build_number = (current_build_number || 0).to_i + 1
     build_ipa(export_method: "app-store", build_number: build_number)
 
+    upload_dsyms_to_crashlytics
+
     upload_to_testflight(
       api_key: appstore_api_key,
       distribute_external: false,