Ensure valid data written to icon_data on windows

src/calibre/gui2/open_with.py

@@ -110,7 +110,7 @@ def finalize_entry(entry):
             data = None
             import traceback
             traceback.print_exc()
-        if data:
+        if isinstance(data, (bytes, bytearray)) or data is None:
             entry['icon_data'] = data
         return entry