QA: Resolve "Failure in qa/specs/features/browser_ui/1_manage/login/register_spec.rb"

What does this MR do?

Sets the initial password if prompted when fabricating a user (which might be the first action in the first test, and so no password is set, at least when the tests are run in CI on the omnibus docker images)

What are the relevant issue numbers?

https://gitlab.com/gitlab-org/quality/nightly/issues/17

Does this MR meet the acceptance criteria?

• Changelog entry added, if necessary
• Documentation created/updated
• Tests added for this feature/bug
• Conforms to the code review guidelines
• Conforms to the merge request performance guidelines
• Conforms to the style guides
• Conforms to the database guides