[Graph Optimization] Add the CUDAGraph usage switch for Draft Model (#4601)

* add draft model using cudagraph switch

* set default as false

* capture draft model in ci

* fix bug

fastdeploy/config.py

@@ -823,6 +823,8 @@ class GraphOptimizationConfig:
         self.real_shape_to_captured_size: dict[int, int] = None
         """ Whether to use shared memory pool for multi capture_size """
         self.use_unique_memory_pool: bool = True
+        """ Whether to use cudagraph for draft model."""
+        self.draft_model_use_cudagraph: bool = False
 
         # CINN Config ...
         if args is not None: