[vertexai] Documentation build warnings

[paulb777]

Description

Several warnings building the documentation for VertexAI

Reproducing the issue

pod-gen FirebaseVertexAI

Product -> Build Documentation

Firebase SDK Version

11.4

Xcode Version

16.1beta

Installation Method

CocoaPods

Firebase Product(s)

VertexAI

Targeted Platforms

iOS, All

Relevant Log Output

If using Swift Package Manager, the project's Package.resolved

Expand Package.resolved snippet

Replace this line with the contents of your Package.resolved.

If using CocoaPods, the project's Podfile.lock

Expand Podfile.lock snippet

Replace this line with the contents of your Podfile.lock!