dji.ux.widget.PreFlightStatusWidget incorrectly reports signal interference for Mavic Air

[JamesMasterman]

• When using the dji.ux.widget.PreFlightStatusWidget, it continually reports "Strong signal interference" when connected to the Mavic Air. When checking in DJI GO or even viewing the Wifi, RC and VideoSignalWidgets in the ux toolkit, it's clear that this is not true. I have also tried flying in very radio quiet areas on a remote farm and it still reports strong interference.

I believe the widget is not reading the signal strength for the Air as it uses Wifi rather than Lightbridge or Ocusync as per other models, and hence incorrectly assumes there is no signal.

• Steps to reproduce the bug or crash issues(It would be great if you can provide this)
  No crash, just connect to a Mavic Air and view the dji.ux.widget.PreFlightStatusWidget.

• DJI Android UILibrary version you are using (UXLibrary v4.5)

• DJI Product you are using (Mavic Air)

• Android system version you are using (All versions of Android - tested on 6, 7 and 8.1)

• Android device you are using (several devices, Huawei media pad M3, Nexus 6P, Samsung Tab A, Samsung S7 phone, Samsung S2 tablet)

• Android Studio version you are using (v 3.1.1)

• Are you using UILibrary Sample Code (No)