Further improve settings for extra tests from GitLab

tests/lakedrops.yml

+variables:
+  DISABLE_CI_TEST_CODESTYLE: 0
+  DISABLE_CI_TEST_BACKSTOP: 0
+
 .test_lakedrops_default: &test_lakedrops_default
   stage: test
   tags:
@@ -33,6 +37,9 @@ Test Code Style:
       - phpcs.xml
   dependencies:
     - 'Build Site'
+  rules:
+    - if: '$DISABLE_CI_TEST_CODESTYLE == "1"'
+      when: never
 
 Test PHPUnit:
   <<: *test_lakedrops_default