network: better error message for wifi scan missing location permission

[xyb994]

Device: Oneplus 6T
Android Version: Android 11

Currently the app display a toast showing "Scan unsuccessful, please try again." when there's no location permission.

Permission violation - startScan not allowed for uid=10958, packageName=io.treehouses.remote, reason=java.lang.SecurityException: UID 10958 has no location permission

Permission violation - getScanResults not allowed for uid=10958, packageName=io.treehouses.remote, reason=java.lang.SecurityException: UID 10958 has no location permission

Consider checking location permission and prompt for enabling it once optimal location permission flow is figured out?