GitLab

- Cards get their "isTestRunning" value from diagnostics-app which
means the property never gets assigned a value when testing these
cards in isolation.
- False makes sense as a default value since all buttons are enabled
initially and it's consistent with the value defined in diagnostics-app.

Bug: 1125150
Test: browser_tests --gtest_filter=DiagnosticsApp*
Change-Id: Ia9bba381691abb5566c01f834c7592d214bc4517
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2616738
Commit-Queue: Michael Checo <michaelcheco@google.com>
Reviewed-by: Zentaro Kavanagh <zentaro@chromium.org>
Cr-Commit-Position: refs/heads/master@{#842746}