fix camera2 crash on low api level

Author: pedroSG94

encoder/src/main/java/com/pedro/encoder/input/sources/video/Camera2Source.kt

@@ -222,7 +222,7 @@ class Camera2Source(context: Context): VideoSource() {
   }
 
   @RequiresApi(Build.VERSION_CODES.P)
-  fun physicalCamerasAvailable() = camera.physicalCamerasAvailable
+  fun physicalCamerasAvailable() = camera.getPhysicalCamerasAvailable()
 
   @RequiresApi(Build.VERSION_CODES.P)
   fun openPhysicalCamera(id: String?) {

encoder/src/main/java/com/pedro/encoder/input/video/Camera2ApiManager.kt

@@ -270,7 +270,9 @@ class Camera2ApiManager(context: Context) : CameraDevice.StateCallback() {
         }
 
     @RequiresApi(Build.VERSION_CODES.P)
-    val physicalCamerasAvailable = cameraCharacteristics?.physicalCameraIds?.toList() ?: emptyList()
+    fun getPhysicalCamerasAvailable(): List<String> {
+        return cameraCharacteristics?.physicalCameraIds?.toList() ?: emptyList()
+    }
 
     @RequiresApi(Build.VERSION_CODES.P)
     fun setPhysicalCamera(id: String?) {