Add support for data-testid attributes

As per gitlab-org/quality/quality-engineering/team-tasks#1822 (closed)

And the MR migrating selectors - gitlab-org/gitlab!124472 (closed)

This MR for Chemlab adds support for data-testid test attributes.

Testing

Update data-qa-selectors eg. ee/app/assets/javascripts/admin/subscriptions/show/components/subscription_breakdown.vue line 170

before	after
data-testid="subscription-details" data-qa-selector="subscription_details" >	data-testid="subscription-details" >

In GitLab project:

Update gemfile to point to this branch

gem 'chemlab', git: 'https://gitlab.com/gitlab-org/quality/chemlab.git', branch: 'qa_selector_testid'

bundle update

and run

CHROME_HEADLESS=false bundle exec bin/qa Test::Instance::All http://gdk.test:3000/ ./qa/specs/features/ee/browser_ui/11_fulfillment/license/license_spec.rb

Should not fail to find selectors.