network: Remove two GtkListStore that were not being used

These had translatable strings in them.
11 jobs for network-unneeded-gtknotebook in 5 minutes and 12 seconds (queued for 3 seconds)
latest
Status Name Job ID Coverage
  Build
passed build #451215

00:02:49

 
  Test
passed asan #451217

00:02:22

passed test #451216

00:00:45

 
  Manual
manual armv8 #451222
allowed to fail manual
manual flatpak #451218
allowed to fail manual
manual msan #451221
allowed to fail manual
manual ppc64le #451223
allowed to fail manual
manual tsan #451219
allowed to fail manual
manual ubsan #451220
allowed to fail manual
 
  Review
manual review #451224
allowed to fail manual
manual stop_review #451225
allowed to fail manual