This didn't actually seem to do anything, resulting in some weird stuff
being enabled by default even though we did not specify a preset for it
(e.g. see !5556)

Based on my interpretation of the systemd preset manpage, this file
should be parsed last. It says that if a unit name has a preset that
was already configured in some previously parsed preset file, then any
matches after do not apply. This means that the `disable *` should not
disable any previously enabled (in previous .preset files) units. When
the unit name is omitted from the `disable` command, it seems to be a no-op.

Fixes !5207