[styles] Make radio button focus ring circular
[styles] Make radio button focus ring circular

We can't use the outline property as this doesn't care about
border-radius which is used to make the radio button circular.

Other places in the codebase use a box shadow to fake a focus ring so
we can use that variable (0 0 0 1px var(--accent-color)) here too.

Picture of fix: https://imgur.com/Y5WXFcW

Bug: chromium:920154
Change-Id: Ie5aae884fa8e4039033141c167ce6419739e171f
Reviewed-on: https://chromium-review.googlesource.com/c/devtools/devtools-frontend/+/2095301
Reviewed-by: Jack Franklin <993fcadce4d04090da2fefd557a0995e7966c8d5@chromium.org>
Commit-Queue: Peter Marshall <6d0eecbeb7fb9d172f49b4b32481d2466fd89429@chromium.org>

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