[NFC] Fix Fatal error on php 8 due to mis matched function declaration

[seamuslee001]

Overview

This fixes the following error on php8

TAP version 13

Fatal error: Declaration of CRM_Contact_Import_Form_MapFieldTest::getFormObject($class, $formValues = [], $pageName = '') must be compatible with CiviUnitTestCase::getFormObject($class, $formValues = [], $pageName = '', $searchFormValues = []) in /home/jenkins/bknix-edge/build/build-0/web/sites/all/modules/civicrm/tests/phpunit/CRM/Contact/Import/Form/MapFieldTest.php on line 135

Before

Tests fail on php8

After

Tests pass on php8

ping @eileenmcnaughton

[civibot]

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