[Firebase AI] Replace FirebaseAILogic SPM library as internal target

[andrewheard]

Removed the FirebaseAILogic SPM library product from Package.swift. This retains FirebaseAI as the only publicly accessible Swift Package product but allows Firebase AI Logic types to be disambiguated, where necessary, using FirebaseAILogic. since all types have been moved into the FirebaseAILogic module and it is transitively exported from FirebaseAI.

Usage Examples:

import FirebaseAI

func apiTests() {
  // No module prefix, same as all existing code snippets
  _ = FirebaseAI.firebaseAI()

  // Module prefixed (FirebaseAILogic is transitively imported)
  _ = FirebaseAILogic.FirebaseAI.firebaseAI()

  // Attempting to prefix with FirebaseAI:
  //   "Type 'FirebaseAI' has no member 'FirebaseAI'"
  // _ = FirebaseAI.FirebaseAI.firebaseAI()
  // Note: This was already broken so no one would be using it.
}

Notes:

• The FirebaseAILogic pod still gets released with this approach. If someone uses pod 'FirebaseAILogic' instead of pod 'FirebaseAI' then they'd need to import FirebaseAILogic instead of import FirebaseAI.
  • Our docs would continue to say pod 'FirebaseAI' so this would only impact devs integrating on their own without docs help -- seems like a non-issue to me since import FirebaseAILogic would auto-complete.
• The zip distribution would contain both FirebaseAI.xcframework and FirebaseAILogic.xcframework (and the instructions would say to add both) -- seems like a non-issue to me.

#no-changelog

[andrewheard]

The quickstart is passing when using the zip from the previous commit.

[paulb777]

Based on our discussion, we can close?

[andrewheard]

Based on our discussion, we can close?

@paulb777 Yep, closing now.