WebUI NTP: prevent OGB cutoff at high zoom levels

Bug: 1146987
Change-Id: I81866a1302d3029d169bb76bb1586f58675fa963
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2535190Reviewed-by: Tibor Goldschwendt <tiborg@chromium.org>
Commit-Queue: Esmael Elmoslimany <aee@chromium.org>
Cr-Commit-Position: refs/heads/master@{#832698}

chrome/browser/resources/new_tab_page/app.html

@@ -56,6 +56,7 @@
     display: flex;
     flex-direction: column;
     height: calc(100vh - var(--ntp-one-google-bar-height));
+    min-width: fit-content;  /* Prevents OneGoogleBar cutoff at 500% zoom. */
     position: relative;
   }