fix http block bug (#4261)

skyvern/forge/sdk/core/aiohttp_helper.py

@@ -58,7 +58,7 @@ async def aiohttp_request(
         # Handle body based on content type and method
         if method.upper() != "GET":
             # If files are provided, use multipart/form-data
-            if files is not None:
+            if files:
                 form = aiohttp.FormData()
 
                 # Add files to form

skyvern/forge/sdk/workflow/models/block.py

@@ -3916,7 +3916,7 @@ class HttpRequestBlock(Block):
 
         # If files are provided, don't set default Content-Type (aiohttp will set multipart/form-data)
         if not self.files:
-            if not self.headers.get("Content-Type") or not self.headers.get("content-type"):
+            if not self.headers.get("Content-Type") and not self.headers.get("content-type"):
                 LOG.info("Adding default content-type as application/json", headers=self.headers)
                 self.headers["Content-Type"] = "application/json"