Update Citations I/O processor for Granite 3.3 LoRA

[yannisk2]

This PR updates the citations I/O processor to support the Granite 3.3 citations generation LoRA.

It contains the following changes:

• Update the citations output processor to work on top of the updated output schema of the Granite 3.3 LoRA (designed to make it easier to perform constrained decoding).
• Updates the citations notebook to use Granite 3.3 to generate the assistant response and the Granite 3.3 citations generation LoRA to generate the citations for that response

Note: The PR currently includes a local copy of the Granite 3.3 citations generation LoRA adapter for testing. Once the LoRA adapter is published on HuggingFace, the PR will be modified to point to the location of the published LoRA adapter instead.

[frreiss]

@yannisk2 thanks for the updates. Would you mind running ruff format on the updated notebook file to clear the CI check?

[yannisk2]

@frreiss FYI, I fixed the linter issues and also updated the unit tests for the citations I/O processor.

[frreiss]

LGTM