Cannot add collection object group to a collection object

[emenslin]

Describe the bug
Introduced in #6073, in the collection object form if you add a collection object group (either creating new or adding existing) and save an error is thrown.

To Reproduce
Steps to reproduce the behavior:

1. Go to CO form
2. Add COG (either create new or add existing)
3. Save
4. See error

Expected behavior
Should not throw an error.

Screenshots
Create new:

01-22-2025_13.40.mp4

Add existing:

01-22-2025_13.43.mp4

Crash Report

Specify 7 Crash Report - 2025-01-22T19_40_42.892Z.txt

Please fill out the following information manually:

• OS: Windows 11
• Browser: Chrome
• Specify 7 Version: production
• Database Name: ojsmnh
• Collection name: fossil invertebrates
• User Name: spadmin
• URL: https://ojsmnh110242024production-production.test.specifysystems.org/specify/

[melton-jason]

This Issue is actually caused by a combination of changes from #6073 and #6038.

Specifically, from:

• 0db66b6: where the logic to handle remote to-one relationships was made generic. The records for remote to-one relationships were being created before the "main" record was being saved without setting the corresponding relationship, and then the relationship was being set from the "concrete" side.
  • In the context of CO/COGs: when creating/updating a CO/COG with information for a cojo, the cojo was being created before the CO/COG was created, and the COJO -> childCo/childCog relationship was only set after both the CO/COG and the COJO were created
• 7be6316: where the businessrules to enforce that a CollectionObjectGroupJoin didn't have neither a childCO or childCOG or both a childCO and childCOG was re-enabled (see Allow to upload COG in WB #6073 (comment))