[Feature] Support preventing Flatpak app from being included in updates (either manual or automatic) aka "masking" with Store UI

[Pentaphon]

Here's the documentation showing how to do this. https://docs.flatpak.org/en/latest/tips-and-tricks.html

This is useful for temporarily preventing a Flatpak application from upgrading to a newer version with bugs that you'd like to avoid until the developer rolls out a newer version in the future that works as intended.