[Frontend] Relax api url assertion for openai benchmarking (vllm-project#6046)

Author: jamestwhedbee

benchmarks/backend_request_func.py

@@ -225,8 +225,8 @@ async def async_request_openai_completions(
 ) -> RequestFuncOutput:
     api_url = request_func_input.api_url
     assert api_url.endswith(
-        "v1/completions"
-    ), "OpenAI Completions API URL must end with 'v1/completions'."
+        "completions"
+    ), "OpenAI Completions API URL must end with 'completions'."
 
     async with aiohttp.ClientSession(timeout=AIOHTTP_TIMEOUT) as session:
         assert not request_func_input.use_beam_search
@@ -304,8 +304,8 @@ async def async_request_openai_chat_completions(
 ) -> RequestFuncOutput:
     api_url = request_func_input.api_url
     assert api_url.endswith(
-        "v1/chat/completions"
-    ), "OpenAI Chat Completions API URL must end with 'v1/chat/completions'."
+        "chat/completions"
+    ), "OpenAI Chat Completions API URL must end with 'chat/completions'."
 
     async with aiohttp.ClientSession(timeout=AIOHTTP_TIMEOUT) as session:
         assert not request_func_input.use_beam_search