fix: also skip FileType.UNK in mime_type detection to preserve fallback behavior

Co-Authored-By: Ryan Waskewich <ryan.waskewich@airbyte.io>

Author: devin-ai-integration[bot]

airbyte_cdk/sources/file_based/file_types/unstructured_parser.py

@@ -407,7 +407,7 @@ def _get_filetype(self, file: IOBase, remote_file: RemoteFile) -> Optional[FileT
         """
         if remote_file.mime_type:
             ft = FileType.from_mime_type(remote_file.mime_type)
-            if ft is not None:
+            if ft is not None and ft != FileType.UNK:
                 return ft
 
         # set name to none, otherwise unstructured will try to get the modified date from the local file system