Import as-needed without implicitly importing UIKit

[L1ghtmann]

What does this implement/fix? Explain your changes.

See title

Checklist

• New code follows the code rules
• I've added modulemaps for any new libraries (e.g. see libactivator/module.modulemap): it should be possible to @import MyLibrary; in ObjC, or import MyLibrary in Swift.
• My contribution is code written by myself from reverse-engineered headers, licensed into the Public Domain as per LICENSE.md; or, code written by myself / taken from an existing project, released under an OSI-approved license, and I've added relevant licensing credit to LICENSE.md

Does this close any currently open issues?

…

Any relevant logs, error output, etc?

Any other comments?

• See successful CI here
• Supersedes Add missing imports to AppSupport/CP*.h #88

Where has this been tested?

Operating System: …

Linux & OSX GitHub-hosted runners

Platform: …

Target Platform: …

Toolchain Version: …

SDK Version: …

[leptos-null]

Thank you for opening this PR. These changes are one of the last to bring this entire repo up to matching the code rules.
These changes also bring the CI duration from 11 minutes to 5 minutes.

[leptos-null]

Looks good to me. Approving on the pre-condition that the associated checks pass