Revert "Feat: enrollments can expire (#1989)"

[angela-tran]

This reverts commit 479b249, reversing changes made to 96ea690.

We're reverting the change to how enrollment is performed to unblock other in-progress changes that we'd like to be able to deploy.

This reverts all the logic for looking up funding sources linked to a group, and determining if a user is eligible for re-enrollment. Instead we go back to handling the 409 error that indicates a user is already enrolled in a group, with no logic for expiration.

We are working with Littlepay to identify issues with testing this expiration logic, and will bring these changes back to dev once we solve those issues.

[github-actions]

Coverage report

Click to see where and how coverage changed

File	Statements	Missing	Coverage	Coverage (new stmts)	Lines missing
benefits
settings.py
benefits/enrollment
views.py
Project Total

This report was generated by python-coverage-comment-action

[thekaveman]

I tested this locally with the Courtesy Card flow, and confirmed that the 409 error was raised and handled during enrollment. I received the success screen.

[angela-tran]

I was also able to get through enrollment successfully using this branch