Add default phone number selection when there is only one

[redryerye]

When I only have one trusted phone number and see the number selection view, I often get confused since it is hard to distinguish a tappable section in the list without a row highlight.
This change will select a phone number as a default when only one option exists.

Single phone number	Multiple phone number

Single phone number with row selected	Multiple phone number with row selected

[MattKiazyk]

Thanks so much @redryerye!