Work around canImport(Combine) being broken in Xcode 13

[kitwtnb]

Checklist

• [x] All tests are passed.
• [x] Added tests.
• [x] Documented the code using Xcode markup.
• [x] Searched existing pull requests for ensure not duplicated.

Description

When using Carbon in Xcode 13, an error occurs during archiving.
Same fix as Realm, Alamofire, etc. https://github.com/realm/realm-cocoa/pull/7401