Adapt shouldAnalyseCSS test to stylelint v17 message change

SonarJS 12.5.0.41048 bumped stylelint from a previous version to v17,
which renamed the message of the "no-invalid-double-slash-comments"
rule from "Unexpected double-slash CSS comment" to "Invalid double-
slash CSS comment". The eclipse standalone IT
StandaloneAnalysisTest#shouldAnalyseCSS asserts on the exact message
text, so it needs updating in lockstep.

Author: nquinquenel

its/org.sonarlint.eclipse.its.standalone/src/org/sonarlint/eclipse/its/standalone/StandaloneAnalysisTest.java

@@ -399,7 +399,7 @@ public void shouldAnalyseCSS() {
 
     var defaultEditor = new DefaultEditor();
     waitForMarkers(defaultEditor,
-      tuple("Unexpected double-slash CSS comment", 1));
+      tuple("Invalid double-slash CSS comment", 1));
   }
 
   @Test