CI: remove redundant macOS 13 CI runs to save the limit of concurrent macOS CI jobs

[Xmader]

GitHub limits the number of concurrent macOS runners to 5. macOS 13 CI runs here are redundant since our binary files built for macos-12 are forward-compatible on macos-13.

I was putting both macos-12 and macos-14 tags here just in order to build on both amd64 and arm64 (macos-14 exclusively) architectures than to differentiate the OS versions. https://github.com/Distributive-Network/PythonMonkey/commit/c402def