fix(react-native-xcode): Add back BUNDLE_COMMAND (#46495)

Summary:
In this PR #45560  the BUNDLE_COMMAND initialization was removed while it is still being used. Without it, building from Xcode throws unknown options error for Physical iOS devices.

I have just brought back the initialization from the PR before that, so the bundle phase is successful.

## Changelog:
[IOS][Fixed] - Add back the BUNDLE_COMMAND

Pull Request resolved: #46495

Test Plan: I have bundled release builds in Xcode. Everything seems to be fine.

Reviewed By: cortinico

Differential Revision: D62846877

Pulled By: cipolleschi

fbshipit-source-id: 3f07e8c0bc5acf98177582f1fee9a55ae77b31a1

packages/react-native/scripts/react-native-xcode.sh

@@ -92,6 +92,8 @@ fi
 
 [ -z "$CLI_PATH" ] && CLI_PATH="$REACT_NATIVE_DIR/scripts/bundle.js"
 
+[ -z "$BUNDLE_COMMAND" ] && BUNDLE_COMMAND="bundle"
+
 [ -z "$COMPOSE_SOURCEMAP_PATH" ] && COMPOSE_SOURCEMAP_PATH="$REACT_NATIVE_DIR/scripts/compose-source-maps.js"
 
 if [[ -z "$BUNDLE_CONFIG" ]]; then