Add collections operations to PineconeControlPlaneClient with integration tests

[austin-denoble]

Problem

The Java SDK is currently missing collections functionality. Now that we've added generated code for the OpenAPI spec, we can hook up collections operations in PineconeControlPlaneClient.

We'd also like to add integration tests to cover collections.

Solution

• Update PineconeControlPlaneClient to include collections operations for create, list, delete, and describe.
• Add new integration test files: CollectionTest and CollectionErrorTest.
• Add new helpers to IndexManager for creating and connecting to an index by indexName, creating a collection and waiting for it to be ready, and polling until an index is ready.
• Add new helper to BuildUpsertRequest for generating vectors by dimension.

Bonuses:

• I added some logging configs in build.gradle for test and the integrationTest task. This was primarily to help me debug things in CI and log a bit more info to the console. We can tweak as needed, but I think having something like this will be really helpful as opposed to the generic output.
• Set max-parallel: 1 in the integration-test job in the pr.yml workflow. Because of the way findIndexWithDimensionAndType works we cannot run integration tests in parallel without flakiness.
• Fixed an issue in AssertRetry. We were incrementing delay at the class level which is a static variable, meaning if you re-used the function in one place it would continue increasing the delay for all subsequent calls based on the backOff.

Type of Change

• New feature (non-breaking change which adds functionality)

Test Plan

Run integration tests to make sure CollectionTest and CollectionErrorTest pass as expected. Integration tests should also be passing in CI barring any flakiness.

[rohanshah18]

Great work!! I have left some comments but one area especially I'd like to think about is the hard-coded time outs added for collection tests in indexManager's waitUntilReady methods.