[signin] Avoid overflow in signin bubbles with long names and emails

This CL uses
overflow-wrap: break-word;
to avoid breaking the bubble layout.
This should happen very rarely.

Screenshot without the fix:
https://drive.google.com/file/d/1SLsl065XjOnZGNt9Y8f3ymjdKUvTcMhK/view

With the fix:
https://drive.google.com/file/d/1SsJ5OnBA9cpHRCESRfbETA7fGfupdiLX/view

Bug: None
Change-Id: Icaf3e99abf1c6119b0c8e3f47b8ad263d6d58d8d
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2520905
Auto-Submit: David Roger <droger@chromium.org>
Commit-Queue: Monica Basta <msalama@chromium.org>
Reviewed-by: Monica Basta <msalama@chromium.org>
Cr-Commit-Position: refs/heads/master@{#824785}

chrome/browser/resources/signin/dice_web_signin_intercept/dice_web_signin_intercept_app.html

@@ -86,6 +86,10 @@
     margin: 0 0 8px;
   }
 
+  #contents {
+    overflow-wrap: break-word;  /** For very long names and emails */
+  }
+
   .action-container {
     padding: 0 16px 16px;
   }