Broken views test config YAML

Follow-up to #2342045: Standard views base fields need to use same rendering as Field UI fields, for formatting, access checking, and translation consistency

The patch there introduced a YAML syntax error in the test_group_rows test view.

This is used by one test: core/modules/views_ui/src/Tests/FilterUITest.php

The test apparently/probably passes. But the API module is not able to parse the file (it must be using a somewhat stricter YAML parsing routing).

The only other files that the API module failed to parse were:
vendor/jcalderonzumba/gastonjs/mkdocs.yml
core/tests/Drupal/Tests/Core/Asset/library_test_files/invalid_file.libraries.yml

I guess we don't fix vendor and the other one presumably is meant to be invalid. ;)

Anyway, it's a one-line patch.