[Mobile Payments] Update connected readers list to show `Built-in reader` when connected for Tap on Mobile

[joshheald]

• Replace Serial number with name of reader for built-in readers
• Consider doing the same for Bluetooth readers, demoting the serial number to a detail of the cell
• Do not show the serial for the built in reader: it's too long and not required.
• Consider hiding any details about "software up to date" for the built in reader

[joshheald]

We won't do this, because we did #8664 instead.