Don't su to 'nemo' when checking network_type

This is a leftover from when NetworkType used to be at
/run/user/100000/state/namespaces/Internet/NetworkType and could be read
only by nemo user. We don't need to su anymore now when it resides in
/run/state.

Fixes a potential hangup on journald crash, since su wants to write into
the journal.