Tests: Rename rest-api group to restapi for consistency.

Rename the group in `tests/phpunit/tests/rest-api/wpIsRestEndpoint.php` to `restapi` for consistency with the group name used by other REST API related tests.

Follow up to [57312].

See #62280.


git-svn-id: https://develop.svn.wordpress.org/trunk@59820 602fd350-edb4-49c9-b593-d223f7449a82

tests/phpunit/tests/rest-api/wpIsRestEndpoint.php

@@ -3,7 +3,7 @@
 /**
  * Tests for the `wp_is_rest_endpoint()` function.
  *
- * @group rest-api
+ * @group restapi
  * @covers ::wp_is_rest_endpoint
  */
 class Tests_Media_Wp_Is_Rest_Endpoint extends WP_UnitTestCase {