fix(admin-ui): Correctly display overlays inside modals

Increased the z-index of the CDK overlay container, otherwise dropdowns are hidden behind the open modal.

packages/admin-ui/src/lib/static/styles/theme/_theme.scss

@@ -70,5 +70,5 @@ table tr .dropdown-menu button.dropdown-item {
 }
 
 .cdk-overlay-container {
-    z-index: 1040;
+    z-index: 1060;
 }