feat(GAT-9463): Allow re-apply for cohort access when expired or rejected

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AI disclaimer - CLAUDE was used for this.

Screenshots / videos (if relevant)

Describe your changes

A user whose Cohort Discovery request ended up Expired or Rejected had no way to apply again: step 1 of the access stepper was marked complete for any non-null status, so the apply button never rendered and those users hit a dead end behind a status chip. The stepper now recognises Expired and Rejected as re-appliable, reopening step 1 with a "Re-apply for access" button that runs the same profile-review then terms-and-conditions flow as a first-time application, with steps 2 and 3 reset to pending. This matches what the API already allows — CohortRequestController::store blocks re-submission only for Pending, Approved, Banned and Suspended — so Banned and Suspended users are deliberately unaffected. The auto-open deep link used by the "Access Cohort Discovery" not-approved modal was widened to cover the same statuses so it now lands on an actionable step, and the qualifying statuses live in one exported const rather than another inline literal.

Issue ticket link

https://hdruk.atlassian.net/browse/GAT-9463

Checklist before requesting a review

• I have performed a self-review of my code
• I have added appropriate unit tests / e2e tests (where relevant)
• I have created mocks for api endpoints (where appropriate)
• The interface is responsive (where ticket is relevant)
• The interface is at least AA (where ticket is relevant)
• Commits are described as "(chore|fix|feature|test|maintenance): description"

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