fix: hide empty modal footers

src/assets/styles/tailwind.css

@@ -183,3 +183,7 @@ thead .fc-day-selected:hover {
     box-shadow: 0 0 0 0.2rem rgba(0, 123, 255, 0.25);
   }
 }
+
+.modal-footer:empty {
+  display: none;
+}