Product name update fails with variant auto-rename feature

[Anddrrew]

Describe the bug
Trying to change a product's name with "Automatically update the names of ProductVariants" selected causes an error.

To Reproduce
Steps to reproduce the behavior:

1. Visit any product page.
2. Edit the product's name.
3. Make sure "Automatically update the names of ProductVariants" is checked.
4. Click the "Update" button.
5. Error message appears: "An error occurred, could not update Product".

Expected behavior
The product and its variants should be renamed without issues.

Environment

• @vendure/core: 2.1.7
• Nodejs: 20.10
• Database: Postgres

Additional context
The bug is related to handling product variants that have a custom field set to readonly: true.

It looks like a type checking problem in the util function
https://github.com/vendure-ecommerce/vendure/blob/master/packages/admin-ui/src/lib/core/src/data/utils/remove-readonly-custom-fields.ts#L106