nightly: set Xcode developer dir explicitly to workaround latest macos runner issue

Author: thymikee

.github/workflows/nightly.yml

@@ -89,6 +89,8 @@ jobs:
 
   build-ios:
     runs-on: macos-latest
+    env:
+      DEVELOPER_DIR: /Applications/Xcode_16.4.0.app/Contents/Developer
     strategy:
       matrix:
         bundler: [metro, repack]