Explicitly handle the case where the iOS device is not paired.  On `flutter run` show an error and bail instead of trying and failing to launch on the device.

On this PR:
```
$ flutter run -d 00008110-0009588C2651401E
'iPhone' is not paired. Open Xcode and trust this computer when prompted.
$
```

Fixes https://github.com/flutter/flutter/issues/144447
Closes https://github.com/flutter/flutter/pull/144095