Revert "package import Foundation.NSData (#231)"

[stephencelis]

This reverts commit 4dfe1b9.

While the syntax works on macOS, that seems to be an Objective-C fluke, and we're seeing failures on Linux now.

@JanGorman I think we'll need some kind of integration-style test to address this. Our Linux CI started failing with this:

Sources/Sharing/Internal/Deprecations.swift:2:18: error: no such module 'Foundation.NSData'
 1 | #if canImport(Foundation)
 2 |   package import Foundation.NSData
   |                  `- error: no such module 'Foundation.NSData'
 3 | #endif
 4 | 

And unfortunately doing the package import class syntax introduces a warning we can't suppress. Ideally there's a workaround that doesn't require a warning that might get accidentally "fixed" later on.

We're going to revert for now, but let us know if you want to dig in deeper.

[JanGorman]

Terribly sorry about that guys. I'll do some digging, most likely the underlying issue is something with our build configuration.

[JanGorman]

Found the underlying issue, it turned out to be our project setup 🙈 #229 (comment)