Allow optional serial number collateral for Heritage Conservation Notice

> _This issue was auto-created as part of the Zenhub sub-issues migration. The original entity was opened on 2022-07-29. For more details see [this post](https://changelog.zenhub.com/migration-of-epics-projects-to-sub-issues-313645?zenhub_entity_id=Z2lkOi8vcmFwdG9yL1plbmh1YkVwaWMvMjA3Nzc0)._

## User Story
As a PPR user, I want to be able to enter serial collateral text for heritage conservation notices so I can fulfill my obligations.

---
## Description
The Heritage Conservation notice [MRR 1(1)(d) and 11(4)] should REQUIRE (mandatory) entry of general collateral text and PERMIT (optional) entry of serial numbered collateral (aka “vehicle” collateral) like the crown charges and other miscellaneous act registrations.

---
### Current Behaviour:

---
### Expected Behaviour
With the exception that there should be no green checkmark beside general collateral until it's provided:

No files or tests are named. Start by locating the Heritage Conservation notice form and its general and serial collateral controls, then trace how their required-state indicators are determined. Done means general collateral is mandatory, serial-numbered collateral is optional, and the general collateral checkmark does not appear before required text is entered.

Written by the indexing model from the issue text.