Display FL from cabin pressure if no external static pressure available

[DanD222]

Is your feature request related to a problem? Please describe.
At present, I see that my iPhone's barometric sensor is used to calculate and display the Cabin Altitude.
I have no external traffic receiver connected to the app:

The FL infobox on the map screen doesn't show a FL value:

Describe the solution you'd like
I would like to have the option to use the phone's internal barometric sensor data to calculate and display the FL value in the FL infobox on the map page.

Additional context
I'm not sure whether the current behaviour is by design - I can imagine it could be, in that it is desirable to calculate FL only from a "proper" static pressure from a static port.

However, if the external traffic receiver is for example a Power Flarm, then I believe that the pressure reported by this device is also the Cabin Altitude, as the device does not have a static port connection and is essentially a box sitting in the cockpit, like the phone.

I could imagine the feature being selectable on the Barometric Data screen, plus also perhaps colouring the FL values in the infobox to indicate that the FL data is calculated from the phone's internal sensor and not from an external device.
This could help to make the user aware of the source the data and warn him to apply extra caution when maintaining vertical airspace separation.