test/test_skip_import_playbook.py: Add name to import_playbook play

Now that ansible-lint is giving an error for plays without name
for import_playbook, add missing name.

Signed-off-by: Arnaud Patard <apatard@hupstream.com>

test/test_skip_import_playbook.py

@@ -25,7 +25,8 @@
     - name: Should be shell  # noqa command-instead-of-shell no-changed-when
       ansible.builtin.shell: echo lol
 
-- import_playbook: imported_playbook.yml
+- name: Should not be imported
+  import_playbook: imported_playbook.yml
 """