remove the word visit for non-us bitcoin links

[jkup]

• Submitted a ticket for my issue if one did not already exist.
• Used Github auto-closing keywords in the commit message.
• Added/updated tests for this change (for new code or code which already has tests).
• Ran git rebase -i to squash commits (if needed).

Auditor: @bradleyrichter

Fix #4212

Test Plan:

Use a VPN or something to fake a non-us address and click the 'add funds' dialog in the payments preferences. Make sure it still gives you a button for cubits or some such but no longer says the word visit.

[bbondy]

++