Updating a variant while specifying same options causes it to conflict with itself

[toBeOfUse]

Describe the bug

In both the Admin API and when using the ProductVariantService directly, if you update a variant and specify that it should have the same options that it already has, there is an error that says that a variant with those options already exists. Instead, I think that updating a variant to have the same options that it already has should be a no-op. It makes it easier to update a variant when you can specify all of the properties that you want it to have, including the options, without triggering errors.

To Reproduce
Steps to reproduce the behavior:

1. Create a variant.
2. Use the updateProductVariants mutation from the Admin API, and specify the option IDs that the variant already has.
3. There is an error.

Here is an example of updating a variant from the test data without specifying optionIds:

Here it is with specifying optionIDs:

Expected behavior
The update should succeed, since it won't cause any harm or inconsistency.

Environment (please complete the following information):

• @vendure/core version: 3.0.5
• Nodejs version: v20.14.0
• Database (mysql/postgres etc): Postgres