Checks that custom fields exist before saving

[spencerrlongg]

Description

This adds a trait that checks that custom fields exist (and exist on the correct fieldset) before saving.

This cannot be merged in it's current form until #14458 is merged, so draft for now.

Fixes [sc-23936]

Type of change

Please delete options that are not relevant.

• Bug fix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)

How Has This Been Tested?

Manually tested for now, custom fields are difficult to test at the moment (Marcus can speak to that better than I can)

Test Configuration:

• PHP version: 8.1
• MySQL version 8.2

[shortcut-integration]

This pull request has been linked to Shortcut Story #23936: Better safeguards against arbitrary field names in API.

[what-the-diff]

PR Summary

• Incorporation of Custom Field Trait in Store Asset Request
  The Store Asset Request now includes a trait called MayContainCustomFields. This enhances the system's capability to handle and process additional information contained in custom fields.

• Introduction of a New File: MayContainCustomFields
  A new file called MayContainCustomFields.php has been added. This houses all the essential functions related to custom fields for more efficient and standardized custom field processing.

• Addition of Validation Messages for Custom Fields
  New validation messages for custom fields have been included in validation.php. This ensures better error handling and user experience when errors occur associated with custom fields.

[spencerrlongg]

Was just curious and wanted to double check, this does actually merge with the error bag from the request's validator and it's the same validator instance, so all validation is included in the same response, which is pretty nice. 🙂

[snipe]

Quick followup here - anything we can do to get this out of WIP?

[uberbrady]

@spencerrlongg Can you re-target this to develop - maybe once you're a little further on out of WIP stage? Thank you!

[spencerrlongg]

Quick followup here - anything we can do to get this out of WIP?

We can talk about #14458, the PR that's holding this one in WIP.

Can you re-target this to develop - maybe once you're a little further on out of WIP stage? Thank you!

It's retargeted, it's only WIP to make sure it doesn't get merged without #14458 - other than that it's ready to go.