UI - Rules - non-schema address rules

#### This task is the remaining, lower-priority work from task #1191.

## Description:
Sub-task of #757.

1. Registered Office Address
-- Delivery Street Address and Address Additional cannot be a PO Box (or any variation)
-- Mailing Street Address can be a PO Box
-- Street Address is optional if Delivery Instructions have data

2. Director Address
-- Residential Street Address and Address Additional cannot be a PO Box (or any variation)

Here's the address component UI interactions and behaviours:
(image in Figma)
https://www.figma.com/design/ji79fDRVt3xjf7sMs8JAPn/Co-op?node-id=14421-130&t=xdmEPoMqzMUfF3RY-1

**Dependencies**
- [x] Ticket #1191 should be done first.

**Acceptance Criteria**
Rules above should be functional.

**Validation Rules**
- [ ] What denotes "a PO Box (or any variation)"?
- [ ] What should error message be? @forgeuxGH5

Ready to Build (DoR):
- [x] Stakeholders have approved
- [x] User story completed
- [x] 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

Review task #1191 and the linked Figma address-component interactions before starting. Confirm what counts as a PO Box variation and what error message to use, since both validation rules are unresolved. Done means the registered-office and director-address rules work for the stated cases, with acceptable test coverage and accessibility review.

Written by the indexing model from the issue text.