CI: Disable testing while it's not possible (lektord headless not implemented)

.gitlab-ci.yml

@@ -81,7 +81,8 @@ build_clang:
 ### Tests #######################################
 #################################################
 
-test_basic:
-    <<: *main_tests
-    stage: test
-    script: scripts/validate.bash --build=clang --step=launch --test=simple
+# Commented because can't launch lektord without any video module.
+# test_basic:
+#     <<: *main_tests
+#     stage: test
+#     script: scripts/validate.bash --build=clang --step=launch --test=simple