Update permission strings (#835)

* Update permission strings

Use an empty string rather than "Not Used" for camera - the Zapbox SDK fills in a default if this is unset.

Add a descriptive permission string for microphone usage.

* More descriptive camera usage

Mac build requires some text, so just go with a generic description that will work for iOS Zapbox build too

Author: tangobravo

Diff for: ProjectSettings/ProjectSettings.asset

@@ -641,9 +641,9 @@ PlayerSettings:
   enableInternalProfiler: 0
   logObjCUncaughtExceptions: 1
   enableCrashReportAPI: 0
-  cameraUsageDescription: Not Used
+  cameraUsageDescription: Camera is required for motion tracking and Mixed Reality
   locationUsageDescription: 
-  microphoneUsageDescription: Not Used
+  microphoneUsageDescription: Microphone is required for voice chat in Multiplayer mode
   bluetoothUsageDescription: 
   macOSTargetOSVersion: 10.13.0
   switchNMETAOverride: