Hide overflowing author element content

In the case of vertical stacking unicode characters it is possible for
the text to overflow out of the element and into other elements on the
review page. This make the page look broken and results in a poor user
experience during code-review.

Partial resolution to:
https://bugs.chromium.org/p/gerrit/issues/detail?id=10795

Change-Id: Ie0d098919e32366873a6de851fab6d00e2b38039
diff --git a/polygerrit-ui/app/elements/change/gr-message/gr-message.html b/polygerrit-ui/app/elements/change/gr-message/gr-message.html
index 32c4c1f..7b49d2a 100644
--- a/polygerrit-ui/app/elements/change/gr-message/gr-message.html
+++ b/polygerrit-ui/app/elements/change/gr-message/gr-message.html
@@ -120,6 +120,7 @@
         position: static;
       }
       .collapsed .author {
+        overflow: hidden;
         color: var(--primary-text-color);
         margin-right: .4em;
       }