Fix group path autofill

What does this MR do?

This adds the missing classes needed for autofilling the group path based on the group name, which are needed since !29271 (merged)

Part of issue: gitlab-org/growth/product#107 (closed)

There is no changelog, since all changes from this MR are behind the experiment onboarding_issues, which is controlled by the feature flag onboarding_issues_experiment_percentage.