Fixed Android export failing when no JDK is setup in the OS environment and custom keystores have been set in the export dialog.

platform/android/export/export_plugin.cpp

@@ -2323,7 +2323,8 @@ static bool has_valid_keystore_credentials(String &r_error_str, const String &p_
 	args.push_back(p_password);
 	args.push_back("-alias");
 	args.push_back(p_username);
-	Error error = OS::get_singleton()->execute("keytool", args, &output, nullptr, true);
+	String keytool_path = EditorExportPlatformAndroid::get_keytool_path();
+	Error error = OS::get_singleton()->execute(keytool_path, args, &output, nullptr, true);
 	String keytool_error = "keytool error:";
 	bool valid = output.substr(0, keytool_error.length()) != keytool_error;