Fix Dismiss button to call expected method

Since Gerrit v3.4.0 the custom Polymer v1 'tap' event is removed and
replaced with the standard 'click' event [1].

[1] 300003: Replace tap by click event | https://gerrit-review.googlesource.com/c/gerrit/+/300003

Change-Id: I700500047780cccc0029d24da55cb837b5380788
Release-Notes: Fixed Dimiss button not persisting until the next day
1 file changed