[Provider Model] UI wording change

- Update the summary of Ethernet network
  "To switch networks, disconnect ethernet"

- Update the summary of data usage for non-carrier networks
  "Excludes data used by carrier networks"

- Update the title of Network preferences
  "Network preferences"

- Screenshot:
  https://screenshot.googleplex.com/62URXVwUJbSXKko
  https://screenshot.googleplex.com/AeZDG2HmkmUkeHd

Bug: 178473018
Bug: 178474159
Bug: 178886957
Test: manual test
Change-Id: Id9ed11ed5cc2db329556bf64a13f21999dcdb151