When testing with local frontend for Android 5 we need ES5 (#2704)

Author: TimoPtr

docs/android/tips/lollipop_emulator.md

@@ -10,3 +10,9 @@ To test the app on an Android emulator running Lollipop (Android API 21), you ne
 ## Updating the WebView
 
 To update the WebView, download the latest WebView APK and follow the instructions provided in this [StackOverflow post](https://stackoverflow.com/a/79514205/3289338).
+
+If you are building your own frontend, set the `ES5` flag to `1` during the build process. This ensures compatibility with the older WebView.
+
+```bash
+ES5=1 script/develop
+```