Fix issues banner button background color on focus
Fix issues banner button background color on focus

Small UI fix to change the background color of the 'View issues' button
when the banner is selected. Also fixed the colors for selected issues
banner in the dark theme.

before: https://i.imgur.com/ZdhYiUv.png
after: https://i.imgur.com/4uMYrj4.png

Bug: chromium:1096481, chromium:1068116
Change-Id: I55deb4519515c419cc7655679a4d64d3aebe7e8c
Reviewed-on: https://chromium-review.googlesource.com/c/devtools/devtools-frontend/+/2339558
Reviewed-by: Sigurd Schneider <f04d242e109628a27a0f75fd49a87722bcf291fd@chromium.org>
Commit-Queue: Wolfgang Beyer <573aa99bb19da47d816981118f95c945310dd3f4@chromium.org>

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