fix: update z-index for intercom app launcher (#15516)

Co-authored-by: Morgan <33722304+ThyMinimalDev@users.noreply.github.com>
Co-authored-by: sean-brydon <55134778+sean-brydon@users.noreply.github.com>

apps/web/styles/globals.css

@@ -479,3 +479,7 @@ select:focus {
 .react-tel-input .flag-dropdown {
   @apply !border-r-default left-0.5 !border-y-0 !border-l-0;
 }
+
+.intercom-lightweight-app  {
+  @apply z-40 !important;
+}