2315 bug declinebydefaultat field is incorrectly being set

[elceebee]

Context

It was noted earlier this month that some application choices have decline_by_default_at dates set. Some, but not all, were set to the actual CycleTimetable.decline_by_default_date.

Now that declining by default is only something that happens at the end of cycle, and is not specific to a single application_form, we no longer need decline_by_default_at or decline_by_default_days on each application_choice

There will be two further PRs:

1. A migration to remove the data from the 40,100 + application choices.
2. A PR to deprecate the columns so we don't start accidentally updating them again in the future.

Changes proposed in this pull request

1. Remove the places in the code where this date was being set:

• The job from 2023
• When an offer is made
• When an offer is reinstated

3. Remove uses / methods related to these columns throughout.
4. Fix flaky spec (unrelated, separate commit)

No real UI changes.

Guidance to review

Sadly, this won't be in in time for any of our 'bug parties', so it would be good if people could use the review app to just check everything is working as expected for making offers / reinstating offers.

Things to check

• If the code removes any existing feature flags, a data migration has also been added to delete the entry from the database
• This code does not rely on migrations in the same Pull Request
• If this code includes a migration adding or changing columns, it also backfills existing records for consistency
• If this code adds a column to the DB, decide whether it needs to be in analytics yml file or analytics blocklist
• API release notes have been updated if necessary
• If it adds a significant user-facing change, is it documented in the CHANGELOG?
• Required environment variables have been updated added to the Azure KeyVault
• Inform data insights team due to database changes
• Make sure all information from the Trello card is in here
• Rebased main
• Cleaned commit history
• Tested by running locally
• Add PR link to Trello card

[github-actions]

You have one or more flakey tests on this branch! ❄️ ❄️ ❄️

Failed 1 out of 3 times at ./spec/system/support_interface/delete_application_spec.rb:7: ⚠️ expected not to find text "Chang" in "First name Change first name"

[elceebee]

Bug: decline_by_default_at field is incorrectly being set

[tomas-stefano]

Take a closer look and everything is good 👍

One small question, is it this PR should remove things like?

1. ReinstateDeclinedOffer#reset_all_dbd
2. time_limit_config chase_candidate_before_dbd rule
3. DBD mention on app/views/support_interface/application_forms/application_choices/reinstate_declined_offer/confirm_reinstate_offer.html.erb

If is not, can you create a small card to handle those any time in the future?

[elceebee]

Great work spotting these other uses, @tomas-stefano. I will add them to this PR. More deleting! Hurrah!