[ts] Typecheck elements/DevicesSettingsTab.js with TypeScript
[ts] Typecheck elements/DevicesSettingsTab.js with TypeScript

Bug: chromium:1011811
Change-Id: I4859d98c64cb168ee55fc369a408b0b16245b694
Reviewed-on: https://chromium-review.googlesource.com/c/devtools/devtools-frontend/+/2521956
Commit-Queue: Tim van der Lippe <dba8716ee7f8d16236046f74d2167cb94410f6ed@chromium.org>
Auto-Submit: Andres Olivares <9d3bededfc9b98cb289557338a8f98e77d597607@chromium.org>
Reviewed-by: Tim van der Lippe <dba8716ee7f8d16236046f74d2167cb94410f6ed@chromium.org>

ChromeDevTools/devtools-frontend,ChromeDevTools/devtools-frontend,ChromeDevTools/devtools-frontend,ChromeDevTools/devtools-frontend,ChromeDevTools/devtools-frontend,ChromeDevTools/devtools-frontend