Simplify write call

aurora/foundry/common/channel.py

@@ -251,9 +251,7 @@ def _mark(self, name: str) -> None:
         with tempfile.TemporaryDirectory() as td:
             mark_file_path = Path(td) / f"{name}.finished"
             mark_file_path.parent.mkdir(exist_ok=True, parents=True)
-            # Write a few bytes to the file. Blob storage has behaved weirdly for empty files.
-            with open(mark_file_path, "wb") as f:
-                f.write(b"File is available")
+            mark_file_path.write_text("File is available")
             self._azcopy(["copy", str(mark_file_path), self._blob_path(f"{name}.finished")])
 
     def _is_marked(self, name: str) -> bool: