altosui: Don't show missing igniter and gps values

altosui: Don't show missing igniter and gps values

The new telemetry stuff leaves state.gps always set (but empty), which
seems fine, we just need to look at state.gps.connected to see if
there's a GPS receiver on board.

For TeleNano, we also want to hide the igniter status fields as they
won't have any data present.

Signed-off-by: Keith Packard <keithp@keithp.com>