IBX-10751: fix missing close tooltip in UDW after search (#1738)

Author: RopRaptor

src/bundle/Resources/public/scss/ui/modules/universal-discovery/mixins/_filters-panel.scss

@@ -10,7 +10,7 @@
         position: sticky;
         top: 0;
         background-color: $ibexa-color-white;
-        z-index: 2;
+        z-index: 1;
         align-items: center;
         justify-content: space-between;
         padding: calculateRem(16px) calculateRem(12px);