Fix deferred course start date on offer deferred

[CatalinVoineag]

Context

Previously, it didn't show the actual date of the course start when it's deferred.

It was showing the date of the current cycle, not the next. So 2024 not 2025 for example

Changes proposed in this pull request

Added deferred_start_date

Guidance to review

Is the logic of the method correct?
Go on the review app and # as a candidate with a deferred offer and check the start date of your course is correct, in the next cycle, should be 2025 for a deferred offer in 2024 cycle

Screencast.2024-09-27.11.47.04.mp4

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

[CatalinVoineag]

Incorrect course start date for deferred offer

[inulty-dfe]

If the application has been deferred, there exists a course in the next cycle with a start date, right? Would it be better to get the start date for that course?

application_choice.current_course.start_date

[elceebee]

We render this same information in the application_status_tag_component.

It is correctly rendered there.

I'm happy with the method you've written, or Iain's suggestion (I don't feel strongly about it). But it would be good to use the same method in both places.

[inulty-dfe]

🚀