As a user I want to be able to choose a custom cessation date for Directors as part of my Annual Report

## Description:
Given I am logged in and I have started my Annual Report Filing
When I want to change director information
Then I can choose a custom past date for that director that doesn't conflict with ANY other filing

**Dependencies**

**Acceptance Criteria**

**Validation Rules**

Ready to Build (DoR):
- [ ] Stakeholders have approved
- [ ] User story completed
- [ ] What are the dependencies
- [ ] Validation rules defined (UI, Data, Role-Action)
- [ ] Is a formal UAT required

Acceptance / DoD:
- [ ] Design / Solution accepted by Product Owner
- [ ] Acceptance criteria has been defined (happy path, known sad paths)
- [ ] Test coverage acceptable
- [ ] Peer Reviewed
- [ ] Accessibility reviewed and acceptable [checklist](https://github.com/bcgov/entity/docs/coding-standards/accessibility.md)
- [ ] UX Approved
- [ ] PR Accepted
- [ ] Production burn in completed

The issue provides no files, tests, or entry points to begin with. Start by locating the Annual Report Filing director-edit flow and the validation for filing-date conflicts; done means a user can select a custom past cessation date that conflicts with no other filing, with the relevant validation and test coverage defined.

Written by the indexing model from the issue text.