Pin keyboard: Justify content on the button with space-between

Needed to align button 1 (w/o text) similar to other buttons

Bug: 1004974
Change-Id: I02be47fc9c865805566182f6982c49341cf26bba
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1862914Reviewed-by: Steven Bennetts <stevenjb@chromium.org>
Reviewed-by: Alexander Alekseev <alemate@chromium.org>
Commit-Queue: Roman Sorokin [CET] <rsorokin@chromium.org>
Cr-Commit-Position: refs/heads/master@{#706356}

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

@@ -107,7 +107,7 @@
         flex-direction: column;
         font-weight: 400;
         height: var(--pin-button-height);
-        justify-content: center;
+        justify-content: space-between;
         margin: 0 var(--pin-button-horizontal-margin);
         min-height: 0;
         min-width: 0;