Devtools: Network tool - Fix FilterBar unexpected selection

This change fixes a bug where the keydown event handler for changing
bits in the UI.FilterBar class was incorrectly causing selection
when trying to navigate at the end of the list. The filter bar
now correctly returns without selection or consuming the event
when an arrow key press does not cause navigation,

Before: https://imgur.com/WQ1x7E0

After: https://imgur.com/nEigQf6

Bug: 1001600

Change-Id: I3b811e26b0238047cdda0d8e751ebdf40102f724
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1790008
Reviewed-by: Joey Arhar <jarhar@chromium.org>
Reviewed-by: Pavel Feldman <pfeldman@chromium.org>
Commit-Queue: Brandon Goddard <brgoddar@microsoft.com>
Cr-Commit-Position: refs/heads/master@{#696537}