feat: Wait one more frame before marking the sidebar as hover, b=no-bug, c=tabs, workspaces

Author: mr-cheffy

src/zen/tabs/zen-tabs/vertical-tabs.css

@@ -809,7 +809,7 @@
   & #titlebar {
     display: grid;
     grid-template-rows: auto 1fr; /* Allow content below button box */
-    overflow: hidden;
+    overflow: clip;
   }
 
   /* Style top buttons customization target */

src/zen/workspaces/ZenWorkspaces.mjs

@@ -562,7 +562,9 @@ var gZenWorkspaces = new (class extends ZenMultiWindowFeature {
         break;
     }
     requestAnimationFrame(() => {
-      gNavToolbox.setAttribute('zen-has-hover', 'true');
+      requestAnimationFrame(() => {
+        gNavToolbox.setAttribute('zen-has-hover', 'true');
+      });
     });
   }