wwan: Handle Updating APN list when device is enabled
requested to merge pabloyoyoista/gnome-control-center:wip/sadiq/fix-wwan-with-device-disabled into main
This is basically !1059 (closed) with an extra one-liner commit:
wwan: wait for apn_list to exist to add SIM providers
This avoids the situation where a duplicate entry is created if
Settings is started with the wwan panel disabled, a previous connection
exists, and the panel is later enabled.
I took the freedom to update this since it's been a while
Fixes #1468 (closed)
Closes !1059 (closed)