Remove default settings parameter fallback from EmulatedDevicesList
constructor.

Bug: 493763857
Change-Id: If731a51f2ec56463e270c3789070e8707407ac3e
TAG=agy
CONV=17f0019a-800c-4e27-9173-706c4d693ec4
Reviewed-on: https://chromium-review.googlesource.com/c/devtools/devtools-frontend/+/8129938
Commit-Queue: Kim-Anh Tran <kimanh@chromium.org>
Reviewed-by: Simon Zünd <szuend@chromium.org>
Commit-Queue: Simon Zünd <szuend@chromium.org>
Auto-Submit: Kim-Anh Tran <kimanh@chromium.org>