### Godot version

3.5.1.stable, v4.0.beta.custom_build [0a87ead64]

### System information

Ubuntu 22.04.1

### Issue description

For example, if project has name "300spartans", we can't enter the "org.godotengine.300spartans" to "Unique Name" field. We get the error "Invalid package name: A digit cannot be the first character in a package segment". But , if we enter "org.godotengine.$genname", there will be no error message. When exporting, the name will be set as "org.godotengine.spartans" without "300" in beginning, but user will not be informed about it. I think, it is not very good. It may not be worth making changes to the source code, but mention it in the documentation.

### Steps to reproduce

See issue description.

### Minimal reproduction project

N/A
}
	}
	if (ep.step(TTR("Running on device..."), 3)) {
		CLEANUP_AND_RETURN(ERR_SKIP);
	}
	args.clear();
	args.push_back("-s");
	args.push_back(devices[p_device].id);
	args.push_back("shell");
	args.push_back("am");
	args.push_back("start");
	if ((bool)EDITOR_GET("export/android/force_system_user") && devices[p_device].api_level >= 17) { 
		args.push_back("--user");
		args.push_back("0");
	}
	args.push_back("-a");
	args.push_back("android.intent.action.MAIN");
	args.push_back("-n");
	args.push_back(get_package_name(package_name) + "/com.godot.game.GodotApp");
	output.clear();
	err = OS::get_singleton()->execute(adb, args, &output, &rv, true);
	print_verbose(output);
	if (err || rv != 0) {
		add_message(EXPORT_MESSAGE_ERROR, TTR("Run"), TTR("Could not execute on device."));
		CLEANUP_AND_RETURN(ERR_CANT_CREATE);
	}
	CLEANUP_AND_RETURN(OK);
#undef CLEANUP_AND_RETURN
}
Ref<Texture2D> EditorExportPlatformAndroid::get_run_icon() const {