Bug 1790232 - Use subviewbutton for the Protections popup buttons and cleanup some CSS r=Gijs

Differential Revision: https://phabricator.services.mozilla.com/D157045

browser/base/content/browser-siteProtections.js

@@ -161,6 +161,7 @@ class ProtectionCategory {
       return false;
     }
     this.categoryItem.classList.toggle("blocked", this.enabled);
+    this.categoryItem.classList.toggle("subviewbutton-nav", this.enabled);
     return true;
   }
 
@@ -1631,6 +1632,10 @@ var gProtectionsHandler = {
         "notFound",
         !blocker.isDetected(event)
       );
+      blocker.categoryItem.classList.toggle(
+        "subviewbutton-nav",
+        blocker.isDetected(event)
+      );
     }
 
     // And the popup attributes: