[Network Settings] Fix auto-connect toggle label for cellular.

This CL changes auto-connect toggle label in the cellular settings page
to read "Automatically connect to cellular network" instead of
"Automatically connect to this network".
Screenshot: https://screenshot.googleplex.com/WfAnZq9Ti4c.png

Bug: 924236
Change-Id: Ic8bdd03cc73baea5584ed38294553798bdc8c87e
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1531706
Reviewed-by: Steven Bennetts <stevenjb@chromium.org>
Reviewed-by: Kyle Horimoto <khorimoto@chromium.org>
Commit-Queue: Azeem Arshad <azeemarshad@chromium.org>
Cr-Commit-Position: refs/heads/master@{#642714}
4 files changed