PDF Viewer: Change alignment of page input to center.

Bug: None
Change-Id: Idb023af45e88fe91e841ee2b1c13ac3c44925145
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2232825Reviewed-by: John Lee <johntlee@chromium.org>
Commit-Queue: dpapad <dpapad@chromium.org>
Cr-Commit-Position: refs/heads/master@{#775777}

chrome/browser/resources/pdf/elements/viewer-page-selector.html

@@ -30,7 +30,6 @@
       #pageselector::part(input) {
         background: rgba(0, 0, 0, 0.5);
         caret-color: var(--cr-input-color);
-        text-align: end;
       }
     </style>
     <cr-input id="pageselector" value="[[pageNo]]" on-mouseup="select"