build: make built dev-app web package writable (#18481)

Bazel by default marks output files as `readonly` to ensure hermeticity.
Since we moved these files out of the `bazel-bin` directory, we should
make the files writable. This is necessary so that subsequent runs of this
script can delete the old `distPath` contents.

Author: devversion

scripts/deploy-dev-app.js

@@ -5,7 +5,7 @@
  * deployed to the currently configured Firebase project.
  */
 
-const {exec, set, cd, cp, rm} = require('shelljs');
+const {exec, set, cd, cp, rm, chmod} = require('shelljs');
 const {join} = require('path');
 
 // ShellJS should throw if any command fails.
@@ -37,5 +37,10 @@ rm('-Rf', distPath);
 // of a public folder outside of the "firebase.json" file.
 cp('-R', webPackagePath, distPath);
 
+// Bazel by default marks output files as `readonly` to ensure hermeticity. Since we moved
+// these files out of the `bazel-bin` directory, we should make them writable. This is necessary
+// so that subsequent runs of this script can delete old contents from the deployment dist folder.
+chmod('-R', 'u+w', distPath);
+
 // Run the Firebase CLI to deploy the hosting target.
 exec(`yarn -s firebase deploy --only hosting`);