Children can be added to one parent COG twice

[lexiclevenger]

Describe the bug
A child CO or COG can be added to the same COG form more than once, resulting in an error.

To Reproduce
Steps to reproduce the behavior:

1. Create a CollectionObjectGroup record
2. Add a CO or COG to the Children subview
3. Add the same CO or COG again
4. Save the base record and see error

Expected behavior
The user should be prevented from saving the record with more than one of the same child. This could be done using a save blocker or by not actually adding the duplicate child to the subview, as seen in subviews like Collecting Event > Collection Object:

Screen.Recording.2025-03-07.at.12.05.07.PM.mov

Screenshots

Screen.Recording.2025-03-07.at.12.01.08.PM.mov

Crash Report

Specify 7 Crash Report - 2025-03-07T18_01_38.796Z.txt

Please fill out the following information manually:

• OS: Mac
• Browser: Chrome
• Specify 7 Version: 7.10.0 and production
• Database Name: ojsmnh_2024_01_10_prod2
• Collection name: Fossil Invertebrates
• User Name: spadmin
• URL: https://ojsmnh20240110prod2-production.test.specifysystems.org/specify/view/collectionobjectgroup/new/