Update strings to be more translation friendly

Use different strings for "None" based on the context of the string.
Some languages may require different gendered grammar depending on its
context.

Also update contacts summary string to include plurals (1 vs many).

Test: make RunSettingsRoboTests7
Bug: 154898476
Fixes: 154944295
Change-Id: If9949d75de573042389a19df3d4c5d15c6cbeb25