chore(ci): Catch xcodebuild log on failure for watchOS sample build in messaging.yml (#15237)

Author: ncooke3

.github/workflows/messaging.yml

@@ -240,4 +240,10 @@ jobs:
       run: sudo xcode-select -s /Applications/Xcode_16.4.app/Contents/Developer
     - name: Build
       run: ([ -z $plist_secret ] || scripts/build.sh MessagingSampleStandaloneWatchApp watchOS)
+    - name: Upload xcodebuild logs
+      if: failure()
+      uses: actions/upload-artifact@v4
+      with:
+        name: xcodebuild-logs-${{ matrix.target }}
+        path: xcodebuild-*.log