[BugFix] fix mm cudagraph

[kevincheng2]

Motivation

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修复多模perfix cache 和 cudagraph 同时开启时，cuda error 700问题

Modifications

Usage or Command

Accuracy Tests

Checklist

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[paddle-bot]

Thanks for your contribution!

[Copilot]

Pull request overview

这个PR修复了多模态（multi-modal）模型同时启用prefix cache和CUDAGraph时出现的cuda error 700问题。通过移除之前强制禁用prefix caching的限制代码，允许这两个特性可以同时工作。

Key Changes

• 移除了在fastdeploy/config.py中当同时启用多模态和CUDAGraph时强制禁用prefix caching的逻辑

[Copilot]

建议在PR描述中补充更详细的信息：

1. 根本原因分析：为什么之前会有cuda error 700错误？是什么改动修复了这个问题？
2. 修复方案说明：为什么移除这个限制就可以解决问题？是否有其他地方的改动配合这个修复？
3. 测试验证：如何验证这个修复是有效的？是否在特定的配置下进行了测试？

更完善的描述有助于未来的维护者理解这个改动的背景和原因。

[Copilot]

This bugfix removes a restriction that was preventing the combination of multi-modal models, prefix caching, and CUDAGraph. While there are existing tests for multi-modal with CUDAGraph (e.g., test_paddleocr_vl_serving.py, test_EB_VL_Lite_sot_serving.py), there doesn't appear to be a test that specifically validates this three-way combination (enable_mm + use_cudagraph + enable_prefix_caching) to prevent regression of the cuda error 700 issue.

Consider adding a test case that explicitly enables all three features together to ensure this bugfix works as expected and to prevent future regressions.

[codecov-commenter]

Codecov Report

✅ All modified and coverable lines are covered by tests.
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Additional details and impacted files

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