[Feature]: AutoDeploy: Enable the gather_logits and analyze this fusion for Piecewise CG

[nvchenghaoz]

🚀 The feature, motivation and pitch

As title, the gather_logits should be enabled by default, and we have to check how to include the final gemm (could include several other ops before the gemm) to the piecewise cudagraph.

Alternatives

No response

Additional context

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