No notification when an update to a flatpak occurs due to low disk space

[mdpenguin]

Describe the bug
When updating a flatpak, if there is not enough disk space to download the update file then mintUpdate refreshes as though it has completed but continues to list the flatpak that didn't update. No error messages are displayed.

To Reproduce
Steps to reproduce the behavior:

1. Create an environment with a large flatpak program installed (e.g. GIMP or Firefox) and low available disk space
2. Run update
3. Note that update appears to complete but flatpaks are still listed to be updated once it refreshes

Expected behavior
Display any error messages from the flatpak update procedure

Distribution:

• Linux Mint

Software version:
Version 6.0.9