Feature Spec for new onboarding experiment

Follow-up from "Onboarding experiment new group step"

The following discussion from !31952 (merged) should be addressed:

• @dosuken123 started a discussion:

  This seems directly jumping to the group form, which technically should start from registering a new user to test !31952 (diffs) and project creation. Hence, there is no much difference on the test coverage between integration tests and e2e tests.

  Does it make sense to rename the feature spec to registrations/user_sees_new_onbording_flow or something and run the test from the begging to the end?