refactor(llm_passthrough_endpoints.py): refactor vertex passthrough to use common llm passthrough handler.py

litellm/proxy/pass_through_endpoints/common_utils.py

@@ -0,0 +1,16 @@
+from fastapi import Request
+
+
+def get_litellm_virtual_key(request: Request) -> str:
+    """
+    Extract and format API key from request headers.
+    Prioritizes x-litellm-api-key over Authorization header.
+
+
+    Vertex JS SDK uses `Authorization` header, we use `x-litellm-api-key` to pass litellm virtual key
+
+    """
+    litellm_api_key = request.headers.get("x-litellm-api-key")
+    if litellm_api_key:
+        return f"Bearer {litellm_api_key}"
+    return request.headers.get("Authorization", "")