test: refine stats value assertion style in endpoint test

Agent-Logs-Url: https://github.com/equalizedigital/accessibility-checker/sessions/7d64c420-7f01-4b61-bcd8-2c36d5c5f786

Co-authored-by: pattonwebz <3902039+pattonwebz@users.noreply.github.com>

Author: Copilot

tests/phpunit/includes/classes/RestApiEndpointsTest.php

@@ -322,7 +322,7 @@ public function test_scans_stats_by_post_types_permissions_and_payload() {
 		if ( ! empty( $data['stats'] ) ) {
 			foreach ( $data['stats'] as $post_type => $stat ) {
 				$this->assertIsString( $post_type );
-				$this->assertTrue( false === $stat || is_array( $stat ) );
+				$this->assertTrue( $stat === false || is_array( $stat ) );
 			}
 		}