All Submissions:

• Have you followed the WooCommerce Contributing guideline?
• Does your code follow the WordPress' coding standards?
• Have you checked to ensure there aren't other open Pull Requests for the same update/change?

Changes proposed in this Pull Request:

Adds the __experimentalOpenMenuOnFocus prop to the attribute and attribute term input select control fields.

Related to #35576 .

• This PR is a very minor change/addition and does not require testing instructions (if checked you can ignore/remove the next section).

How to test the changes in this Pull Request:

1. Load this branch, build it, and make sure you have the new-product-management-experience feature flag enabled (you can do so using the latest version of the Beta tester within the mono repo).
2. Go to Products > Attributes and add some attributes
3. Go to Product > Add New and scroll down to the attributes field
4. Select Add first attribute and select the attribute input field
5. The menu should open with the initial list of attributes
6. Select an attribute that contains a couple terms
7. Once selected the attribute term field should auto focus and open, it might initially show a loading icon, but then a list of terms.

Other information:

• Have you added an explanation of what your changes do and why you'd like us to include them?
• Have you written new tests for your changes, as applicable?
• Have you created a changelog file for each project being changed, ie pnpm --filter=<project> changelog add?

FOR PR REVIEWER ONLY:

• I have reviewed that everything is sanitized/escaped appropriately for any SQL or XSS injection possibilities. I made sure Linting is not ignored or disabled.