Remove third-party VPN combined name
VpnService concatenates the third-party VPN provider's extension name
and the user-provided configuration name into a combined name in a
non-18n-aware manner. This CL removes the concatenation. The extension
name and configuration name will be combined visually by the UI as
required instead.
BUG=434711,460428
TEST=Manual, together with follow-up CLs that wire up the UI
Review URL: https://codereview.chromium.org/
990993003
Cr-Commit-Position: refs/heads/master@{#319870}