Duplicate function - divide & conquer

Revert "SearchKit - Use POST to send contact ids to action forms"

This reverts commit 1297a574.

[NFC] Remove weird file

SearchKit - Make inline edit only available when applicable

Add unit tests to cover date field imports

Fixes #3423
Ensures that custom fields for one entity sub-type (e.g. Individual) are not
presented as editable for other sub-types (e.g. Organiztion).

[Import] Remove empty if

Remove always-true if-check

SearchKit - Fix in-place editing custom relationship fields

[Import] Remove handling for unavailable field current_employer

[Import] Fix & test check on contact subtype change

[Import] Check subtype validity in validate rather than wait for 'imort'

Before: In-place edit updates the wrong record for custom relationship fields
After: Fixed

Fixes #3475 - Allow 'yesno' as a valid value of `html_type`

SearchKit - Use POST to send contact ids to action forms

Ensure setting deceased date sets is_deceased in the BAO

Payment forms test fixes

Re-use code in test

[REF] Move list of fields that have been upgraded

[NFC] Improve comment blocks for mapper

[Ref] [Import] Cleanup function return