Refactor generate_benchmark_report to set default values for parameters

Author: anmarques

src/guidellm/main.py

@@ -186,17 +186,17 @@ def generate_benchmark_report_cli(
 
 def generate_benchmark_report(
     target: str,
-    backend: BackendEnginePublic,
-    model: Optional[str],
     data: Optional[str],
     data_type: Literal["emulated", "file", "transformers"],
-    tokenizer: Optional[str],
-    rate_type: ProfileGenerationMode,
-    rate: Optional[float],
-    max_seconds: Optional[int],
-    max_requests: Union[Literal["dataset"], int, None],
-    output_path: str,
-    cont_refresh_table: bool,
+    backend: BackendEnginePublic="openai_server",
+    model: Optional[str]=None,
+    tokenizer: Optional[str]=None,
+    rate_type: ProfileGenerationMode="sweep",
+    rate: Optional[float]=None,
+    max_seconds: Optional[int]=120,
+    max_requests: Union[Literal["dataset"], int, None]=None,
+    output_path: str=None,
+    cont_refresh_table: bool=False,
 ) -> GuidanceReport:
     """
     Generate a benchmark report for a specified backend and dataset.