ref: Use forward declarations in header

[github-actions]

Note

The pull request "ref: Use forward declarations in header" was created by @noahsmartin but did not reference an issue. Therefore this issue was created for better visibility in external tools like Linear.

Cleans up a few imports which will make the swift migration a bit easier and improve the output of the migration script

#skip-changelog

[linear]

COCOA-735 ref: Use forward declarations in header