eslint: enable no-useless-escape checks
eslint: enable no-useless-escape checks

Change-Id: Ic2367b09e16a6036e81b4a7be11df29d34bc78ed
Reviewed-on: https://chromium-review.googlesource.com/c/apps/libapps/+/2141054
Reviewed-by: Joel Hockey <9ecfc52dc2ffef73afac73f3495f294aeddf1231@chromium.org>
Tested-by: kokoro <2ac7b1f3fa578934c95181d4272be0d3bca00121@google.com>

chromium/hterm,chromium/hterm,chromium/hterm,chromium/hterm