fix(theme-shared): correct toast-container component z-index

npm/ng-packs/packages/theme-shared/src/lib/components/toast-container/toast-container.component.scss

@@ -6,6 +6,7 @@
   justify-content: flex-end;
   min-width: 350px;
   min-height: 80px;
+  z-index: 1900;
   &.new-on-top {
     flex-direction: column-reverse;
   }