frontend-ng DomService karma test failure

Test started failing last week, compare assertion failed with different -webkit-app-region.

Could be related with Chrome update from 66.0.3359.139 to 67.0.3396.99

-webkit-app-region: no-drag

became:

-webkit-app-region: none

17:12:05 ✖ 1 test failed
17:12:05 
17:12:05 FAILED TESTS:
17:12:05   DomService
17:12:05     ✖ can copy the computed style of descendants
17:12:05       HeadlessChrome 67.0.3396 (Linux 0.0.0)

See https://builds.onehippo.org/job/cms_hippo-addon-channel-manager/job/release%252F4.2/8/console