[Feature Request] Add "hold device flat" indicator

[ahmd-sh]

Checklist

• I've checked that there is no other issue about this feature request.
• This issue contains only one feature request.
• The title of this issue accurately describes the feature request.

Feature description

There needs to be an indicator prompting the user to hold their device flat, using gyroscope readings or other sensors. The indicator needs to be gracefully implemented in the design and should look part of the current design language.

Why do you want this feature?

Holding the device flat ensures the most accuracy when following the compass arrow. It will ensure the best possible representation of the direction in which the user is facing.

Additional information

No response