### 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
Vector<uint8_t> data;
		_load_image_data(splash_bg_color_image, data);
		store_image(SPLASH_BG_COLOR_PATH, data);
	}
	
	
	for (int i = 0; i < icon_densities_count; ++i) {
		if (main_image.is_valid() && !main_image->is_empty()) {
			print_verbose("Processing launcher icon for dimension " + itos(launcher_icons[i].dimensions) + " into " + launcher_icons[i].export_path);
			Vector<uint8_t> data;
			_process_launcher_icons(launcher_icons[i].export_path, main_image, launcher_icons[i].dimensions, data);
			store_image(launcher_icons[i], data);
		}
		if (foreground.is_valid() && !foreground->is_empty()) {
			print_verbose("Processing launcher adaptive icon foreground for dimension " + itos(launcher_adaptive_icon_foregrounds[i].dimensions) + " into " + launcher_adaptive_icon_foregrounds[i].export_path);
			Vector<uint8_t> data;
			_process_launcher_icons(launcher_adaptive_icon_foregrounds[i].export_path, foreground,
					launcher_adaptive_icon_foregrounds[i].dimensions, data);
			store_image(launcher_adaptive_icon_foregrounds[i], data);
		}
		if (background.is_valid() && !background->is_empty()) {
			print_verbose("Processing launcher adaptive icon background for dimension " + itos(launcher_adaptive_icon_backgrounds[i].dimensions) + " into " + launcher_adaptive_icon_backgrounds[i].export_path);
			Vector<uint8_t> data;
			_process_launcher_icons(launcher_adaptive_icon_backgrounds[i].export_path, background,
					launcher_adaptive_icon_backgrounds[i].dimensions, data);
			store_image(launcher_adaptive_icon_backgrounds[i], data);
		}
	}
}
Vector<EditorExportPlatformAndroid::ABI> EditorExportPlatformAndroid::get_enabled_abis(const Ref<EditorExportPreset> &p_preset) {