wait files fully downloaded before complete task (#1707)

skyvern/exceptions.py

@@ -1,3 +1,5 @@
+from pathlib import Path
+
 from fastapi import status
 
 
@@ -252,6 +254,12 @@ class DownloadFileMaxSizeExceeded(SkyvernException):
         super().__init__(f"Download file size exceeded the maximum allowed size of {max_size} MB.")
 
 
+class DownloadFileMaxWaitingTime(SkyvernException):
+    def __init__(self, downloading_files: list[Path]) -> None:
+        self.downloading_files = downloading_files
+        super().__init__(f"Long-time downloading files [{downloading_files}].")
+
+
 class NoFileDownloadTriggered(SkyvernException):
     def __init__(self, element_id: str) -> None:
         super().__init__(f"Clicking on element doesn't trigger the file download. element_id={element_id}")