Cleanup `about_your_company_registration_flow` feature flag

What does this MR do and why?

• cleanup/commit to the enabled path of the mentioned feature flag - see rollout issue #355909 (closed)
  • has been enabled in staging and production for many months now.

Screenshots or screen recordings

no change in this MR, but see !82529 (merged) for the company form path we are committing to here.

MR acceptance checklist

This checklist encourages us to confirm any changes have been analyzed to reduce risks in quality, performance, reliability, security, and maintainability.

• I have evaluated the MR acceptance checklist for this MR.

Related to #371550 (closed)