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:

This PR adds support for a suffix prop on __experimentalSelectControl.

New tests and stories were also added.

According to the acceptance criteria in #35426:

• The suffix is shown on the right hand side of the select control's input field
• If no suffix is set, a search icon is shown as the suffix
• If a suffix is set, it is used instead of the default

Additionally (this wasn't spelled out in the acceptance criteria):

• If suffix is set to null, no suffix is shown

I decided that a SelectControlSuffixWrapper wasn't necessary at this time. We have no immediate need for it, and we are providing a SuffixIcon component that can be used to easily set a custom icon while maintaining the correct styling.

If a need for a SelectControlSuffixWrapper arises in the future it will be addressed in a separate PR.

Closes #35426.

• 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. Run unit tests: pnpm --filter=@woocommerce/components run test -- src/experimental-select-control
2. Interact with Storybook and make sure experimental > SelectControl stories render correctly. Especially the new, suffix-specific ones:
   • Custom Suffix
   • Custom Suffix icon
   • Default Suffix
   • No Suffix
3. Go to Products > Add new (MVP)
4. Verify the Categories select control renders properly

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.