Chrome OS: Set pin setup dots letter spacing to 18px.

Bug: 905455
Change-Id: I45beaa8dee4cd4aec6056a8e2be7df342726ae02
Reviewed-on: https://chromium-review.googlesource.com/c/1336488Reviewed-by: Wenzhao (Colin) Zang <wzang@chromium.org>
Commit-Queue: Alexander Alekseev <alemate@chromium.org>
Cr-Commit-Position: refs/heads/master@{#608172}

ui/webui/resources/cr_components/chromeos/quick_unlock/pin_keyboard.html

@@ -160,7 +160,7 @@
         --cr-input-error-display: none;
         --cr-input-input: {
           font-size: 28px;
-          letter-spacing: 28px;
+          letter-spacing: 18px;
         };
         --cr-input-padding-bottom: 1px;
         --cr-input-padding-end: 0;