### 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
r_features->push_back("mobile");
	r_features->push_back("android");
}
void EditorExportPlatformAndroid::resolve_platform_feature_priorities(const Ref<EditorExportPreset> &p_preset, HashSet<String> &p_features) {
}
EditorExportPlatformAndroid::EditorExportPlatformAndroid() {
#ifdef MODULE_SVG_ENABLED
	Ref<Image> img = memnew(Image);
	const bool upsample = !Math::is_equal_approx(Math::round(EDSCALE), EDSCALE);
	ImageLoaderSVG img_loader;
	img_loader.create_image_from_string(img, _android_logo_svg, EDSCALE, upsample, false);
	logo = ImageTexture::create_from_image(img);
	img_loader.create_image_from_string(img, _android_run_icon_svg, EDSCALE, upsample, false);
	run_icon = ImageTexture::create_from_image(img);
#endif
	devices_changed.set();
	plugins_changed.set();
#ifndef ANDROID_ENABLED
	check_for_changes_thread.start(_check_for_changes_poll_thread, this);
#endif
}
EditorExportPlatformAndroid::~EditorExportPlatformAndroid() {
#ifndef ANDROID_ENABLED
	quit_request.set();
	check_for_changes_thread.wait_to_finish();
#endif
}