[MEVD] Port the Pinecone connector to use Pinecone.Client

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The current Pinecone connector uses Pinecone.NET, which is the older community-written SDK; Pinecone have since published an official, internally-developed SDK called Pinecone.Client, which is shown in official C# samples in their documentation etc.

In addition, in my attempts to set up container-based integration tests with the Pinecone local emulator, the current connector failed to work properly, whereas Pinecone.Client works well.

In other words, it looks like we'll need to port over the Pinecone connector to use the newer, official Pinecone.Local SDK.

Once that's done, also create an integration test suite like the others from #10273, and implement LINQ-based filtering.