When POST-ing or PUT-ing asset record, clear hidden fields

Created by: joeadams04

When editing an asset:

Setting Personal Data to true enables all pd fields below, such as data subject and data category. Multiple choices can be made in these selection fields, which update the current asset state. If a user then decides to set Personal Data to false, all the pd fields that were previously enabled should cleared and reset to null.

Unlikely this will happen much, as you'd think the user would be confident there is personal data if they start filling out the questions underneath. However, we need to make sure it's impossible they can return a value in all the pd fields while pd = false.