Modify Plugin Function in Theme Functions.php

plugin-functions.php

public function enqueue_scripts() {

		// Empty redirect.
		$redirect_fail = '';

		// Set the redirect URL.
		$redirectOnFail = esc_url( apply_filters( 'avwp_redirect_on_fail_link', $redirect_fail ) );
}

theme-functions.php

add_filter('avwp_redirect_on_fail_link', 'modify_plugin_function');

function modify_plugin_function($redirect_fail){
    return $redirect_fail = 'http://www.google.com';
}