Revert "Roll DevTools Frontend from 5166fad523bf to 1e6a1e2ee228 (3 revisions)"

This reverts commit 54f471cc.

Reason for revert: crbug.com/1184695

Original change's description:
> Roll DevTools Frontend from 5166fad523bf to 1e6a1e2ee228 (3 revisions)
>
> https://chromium.googlesource.com/devtools/devtools-frontend.git/+log/5166fad523bf..1e6a1e2ee228
>
> 2021-03-04 petermarshall@chromium.org [l10n] Add checks for ICU plural format in collect-strings
> 2021-03-04 devtools-ci-autoroll-builder@chops-service-accounts.iam.gserviceaccount.com Update DevTools DEPS.
> 2021-03-04 jacktfranklin@chromium.org [Theme Colors] exempt var(--image-file-*) from rule
>
> If this roll has caused a breakage, revert this CL and stop the roller
> using the controls here:
> https://autoroll.skia.org/r/devtools-frontend-chromium
> Please CC devtools-waterfall-sheriff-onduty@grotations.appspotmail.com on the revert to ensure that a human
> is aware of the problem.
>
> To report a problem with the AutoRoller itself, please file a bug:
> https://bugs.chromium.org/p/skia/issues/entry?template=Autoroller+Bug
>
> Documentation for the AutoRoller is here:
> https://skia.googlesource.com/buildbot/+doc/master/autoroll/README.md
>
> Bug: chromium:1163928
> Tbr: devtools-waterfall-sheriff-onduty@grotations.appspotmail.com
> Change-Id: Iff4e1ac4d63391004d4698acee0c4798ecb71b3f
> Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2735177
> Commit-Queue: chromium-autoroll <chromium-autoroll@skia-public.iam.gserviceaccount.com>
> Bot-Commit: chromium-autoroll <chromium-autoroll@skia-public.iam.gserviceaccount.com>
> Cr-Commit-Position: refs/heads/master@{#859753}

Bug: chromium:1163928, chromium:1184695
Change-Id: I497761dbdabec8968cd99705c2eaa3dfbc39107b
No-Presubmit: true
No-Tree-Checks: true
No-Try: true
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2736055
Commit-Queue: François Doray <fdoray@chromium.org>
Bot-Commit: Rubber Stamper <rubber-stamper@appspot.gserviceaccount.com>
Cr-Commit-Position: refs/heads/master@{#859768}