[utilities] Remove call-site of Array#remove from CSSModel
[utilities] Remove call-site of Array#remove from CSSModel

TBR=jacktfranklin@chromium.org

Bug: chromium:1050549
Change-Id: Ifa67757255c23adc89e1f2976d4e8b74bdebcfbe
Reviewed-on: https://chromium-review.googlesource.com/c/devtools/devtools-frontend/+/2096704
Reviewed-by: Simon Zünd <38944668e9e2ca98ccd0275b53370f90fa55c113@chromium.org>
Reviewed-by: Tim van der Lippe <dba8716ee7f8d16236046f74d2167cb94410f6ed@chromium.org>
Commit-Queue: Simon Zünd <38944668e9e2ca98ccd0275b53370f90fa55c113@chromium.org>

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