Comment 15 for bug 1962021

The upgrade dialog says:

```
Upgrade to the firefox snap Starting in Ubuntu 22.04, all new releases of firefox are only available to Ubuntu users through the snap package.
This package update will transition your system over to the snap by installing it. It is recommended to close all open firefox windows before proceeding to the upgrade.
<OK>
```

Is it possible to add a <Cancel> button there, so that people that don't want to install snap get a chance to cancel that upgrade, so that they uninstall firefox first, and then resume with their `apt full-upgrade`s?