[fsdp] fix: change geo3k model name from non-vl to vl

[nanjiangwill]

What does this PR do?

Fix geo3k script model_name from non vl model to vl model

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[gemini-code-assist]

Code Review

This pull request updates the model path from a non-Vision-Language model to a Vision-Language model across three experiment scripts. To improve maintainability, consider centralizing the model path configuration to avoid duplication.