Remove watchOS Support or Implement Custom Build Script in Package.swift

[tiepvuvan]

Issue description:

Upon reviewing the Package.swift for the repository, it indicates that the package supports watchOS.
However, it's worth noting that the firebase-ios-sdk currently does not offer xcframeworks built specifically for watchOS. As a result, this might trigger build errors when trying to compile projects targeting watchOS with this package.

To address this, I'd recommend either:

• Removing the watchOS support from the Package.swift to reflect the true capabilities of the package or
• Incorporating a custom build script to handle watchOS compilation.

Related issues:

• FR: Support watchOS platform in xcframework, Carthage distribution firebase/firebase-ios-sdk#8731

Thank you for looking into this.

[WillBishop]

Any progress on this? The linked issue on the Firebase repo indicates that the work might be done?, but I still get build errors while trying to use these packages with my project that has an Apple Watch target: