Properly detect incorrect usage of CSS combinators

Related discussion:
- https://www.reddit.com/r/uBlockOrigin/comments/12fquk4/ublock_is_on_but_im_still_getting_ads_on_this/jfpkz1g/

src/js/static-filtering-parser.js

@@ -3093,6 +3093,7 @@ class ExtSelectorCompiler {
         if ( parts === undefined ) { return; }
         if ( this.astHasType(parts, 'Error') ) { return; }
         if ( this.astHasType(parts, 'Selector') === false ) { return; }
+        if ( this.astIsValidSelectorList(parts) === false ) { return; }
         if (
             this.astHasType(parts, 'ProceduralSelector') === false &&
             this.astHasType(parts, 'ActionSelector') === false