Add support for models api

[rohanshah18]

Problem

Add support for models api.

Solution

This PR contains following changes:

1. Regenerated code based on the latest changes in the 2025-04 OAS
2. Added listProjectBackups(Integer limit, String paginationToken)
3. Added support for models api by adding the following methods:
   1. listModels()
   2. listModels(String type)
   3. listModels(String type, String vectorType)
   4. describeModel(String modelName)
4. Added integration test for various list and describe model methods.

Following code shows how to list and describe an embedding model:

import io.pinecone.clients.Inference;
import io.pinecone.clients.Pinecone;
import org.openapitools.inference.client.ApiException;
import org.openapitools.inference.client.model.ModelInfo;
import org.openapitools.inference.client.model.ModelInfoList;
...

Pinecone pinecone = new Pinecone
        .Builder(System.getenv("PINECONE_API_KEY"))
        .build();

Inference inference = pinecone.getInferenceClient();

// list models
ModelInfoList models = inference.listModels();
System.out.println(models);

// list models by filtering with type
models = inference.listModels("rerank");
System.out.println(models);

// list models by filtering with type and vectorType
models = inference.listModels("embed", "dense");
System.out.println(models);

// describe a model
ModelInfo modelInfo = inference.describeModel("llama-text-embed-v2");
System.out.println(modelInfo);

Type of Change

• Bug fix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Breaking change (fix or feature that would cause existing functionality to not work as expected)
• This change requires a documentation update
• Infrastructure change (CI configs, etc)
• Non-code change (docs, etc)
• None of the above: (explain here)

Test Plan

Added integration tests.

[austin-denoble]

LGTM, just a couple nits.