Add support for TerraTorch Geospatial models served via the vLLM /pooling endpoint

[mgazz]

Summary

This PR adds support for TerraTorch Geospatial models like Prithvi. Compared to traditional LLMs, Geospatial Models support image-to-image or tensor-to-tensor input/output, but they do not process text. Moreover they are served in vLLM at the /pooling endpoint.

Details

• Support for the /pooling endpoint
• A custom PoolingColumnMapper to map the prompt entry in datasets without creating conflict with the existing GenerativeColumnMapper
• A new request handler for the pooling endpoint: PoolingRequestHandler

Test Plan

Related Issues

• Resolves Add support for Geospatial models (served via vLLM) #587

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Use of AI

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• Includes AI-generated tests (NOTE: AI written tests should have a docstring that includes ## WRITTEN BY AI ##)