### 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
for (int i = 0; i < p_so.tags.size(); ++i) {
		int abi_index = -1;
		for (int j = 0; j < abis.size(); ++j) {
			if (abis[j].abi == p_so.tags[i] || abis[j].arch == p_so.tags[i]) {
				abi_index = j;
				break;
			}
		}
		if (abi_index != -1) {
			exported = true;
			String base = "res://android/build/libs";
			String type = export_data->debug ? "debug" : "release";
			String abi = abis[abi_index].abi;
			String filename = p_so.path.get_file();
			String dst_path = base.path_join(type).path_join(abi).path_join(filename);
			Vector<uint8_t> data = FileAccess::get_file_as_bytes(p_so.path);
			print_verbose("Copying .so file from " + p_so.path + " to " + dst_path);
			Error err = store_file_at_path(dst_path, data);
			ERR_FAIL_COND_V_MSG(err, err, "Failed to copy .so file from " + p_so.path + " to " + dst_path);
			export_data->libs.push_back(dst_path);
		}
	}
	ERR_FAIL_COND_V_MSG(!exported, FAILED,
			"Cannot determine architecture for library \"" + p_so.path + "\". One of the supported architectures must be used as a tag:" + join_abis(abis, " ", true));
	return OK;
}
bool EditorExportPlatformAndroid::_has_read_write_storage_permission(const Vector<String> &p_permissions) {
	return p_permissions.find("android.permission.READ_EXTERNAL_STORAGE") != -1 || p_permissions.find("android.permission.WRITE_EXTERNAL_STORAGE") != -1;
}
bool EditorExportPlatformAndroid::_has_manage_external_storage_permission(const Vector<String> &p_permissions) {