meta: remove unneeded .mailmap entry

The previous Perl script used to generate the AUTHORS file (probably)
needed more entries than the current JS script to avoid duplicate
entries in AUTHORS. The entry removed here is no longer needed for that
purpose, but it is creating a small issue around tooling for gathering
contributor metrics.

Author: Trott

.mailmap

@@ -63,7 +63,6 @@ Bidisha Pyne <pyne.bidisha2017@gmail.com> <bidipyne@in.ibm.com>
 bl-ue <bl-ue@users.noreply.github.com> bl-ue <54780737+bl-ue@users.noreply.github.com>
 Brad Decker <bhdecker84@gmail.com>
 Brad Larson <brad@waterfallmedia.net>
-Bradley Meck <bradley.meck@gmail.com>
 Brandon Benvie <brandon@bbenvie.com> <brandon@brandonbenvie.com>
 Brandon Kobel <kobelb@gmail.com> kobelb <brandon.kobel@elastic.co>
 Brendan Ashworth <brendan.ashworth@me.com> <squirrelslikeacorns@gmail.com>