pid1: order .automount units after local-fs-pre.target

pid1: order .automount units after local-fs-pre.target

From the bug:
> According to the documentation of systemd.automount if the automoint point is
> automagically created if it doesn't exist yet. This ofcourse means the
> filesystem underneath has to be writable, which for / means not only does
> -.mount need to be started but also systemd-remount-fs.service has to be run,
> which isn't guaranteed by the default automount dependencies.
>
> For .mount units there is an automatic default After= dependency on
> local-fs-pre.target, would probably make sense to do the same for automount
> units to avoid it failing on the corner-case where it has to create directory.

Fixes #13306.