Fix HBC_SOURCEMAP_FILE in scripts/react-native-xcode.sh (#34111)

Summary:
## Summary

Fixes #32497
Fixes #34212

The assigned HBC_SOURCEMAP_FILE path is incorrect as it does not reference the hermes bundle source map file

See: #32497 (comment)

## Changelog
[General] [Fixed] - using SOURCEMAP_FILE during xcode build phase with Hermes enabled

Pull Request resolved: #34111

Test Plan:
1. In a blank react-native project
1. Enable Hermes
1. Go to xCode -> Project -> Build Phases -> Bundle React Native code and images
3. Add `export SOURCEMAP_FILE="$(pwd)/../ios.jsbundle.map"` before `react-native-xcode.sh`
   e.g.
   ```sh
   export NODE_BINARY=node
   export SOURCEMAP_FILE="$(pwd)/../ios.jsbundle.map"

   ../node_modules/react-native/scripts/react-native-xcode.sh
   ```
4. Make a release build `npx react-native run-ios --configuration Release` or `CMD + I` in xCode
5. Verify the build is successful
6. Verify the `.map` file is outputted at the specified path (`ios.jsbundle.map` in project root for the example above)

Reviewed By: cipolleschi

Differential Revision: D38460586

Pulled By: dmitryrykun

fbshipit-source-id: 54c1594b37fa2253896ce9739c1a9a712deecd0f

scripts/react-native-xcode.sh

@@ -168,7 +168,7 @@ else
   fi
   "$HERMES_CLI_PATH" -emit-binary $EXTRA_COMPILER_ARGS -out "$DEST/main.jsbundle" "$BUNDLE_FILE"
   if [[ $EMIT_SOURCEMAP == true ]]; then
-    HBC_SOURCEMAP_FILE="$BUNDLE_FILE.map"
+    HBC_SOURCEMAP_FILE="$DEST/main.jsbundle.map"
     "$NODE_BINARY" "$COMPOSE_SOURCEMAP_PATH" "$PACKAGER_SOURCEMAP_FILE" "$HBC_SOURCEMAP_FILE" -o "$SOURCEMAP_FILE"
   fi
   BUNDLE_FILE="$DEST/main.jsbundle"