added projection field to sensor data

com.unity.perception/Runtime/GroundTruth/DatasetJsonUtility.cs

                 case double v:
                     return new JValue(v);
                 case string v:
-                    return new JValue($"\"{v}\"");
+                    return new JValue(v);
                 case uint v:
                     return new JValue(v);
             }

com.unity.perception/Runtime/GroundTruth/PerceptionCamera.cs

             // Record the camera's projection matrix
             SetPersistentSensorData("camera_intrinsic", ToProjectionMatrix3x3(cam.projectionMatrix));
 
+            // Record the camera's projection type (orthographic or perspective)
+            SetPersistentSensorData("projection", cam.orthographic ? "orthographic" : "perspective");
+
             var captureFilename = $"{Manager.Instance.GetDirectoryFor(rgbDirectory)}/{k_RgbFilePrefix}{Time.frameCount}.png";
             var dxRootPath = $"{rgbDirectory}/{k_RgbFilePrefix}{Time.frameCount}.png";
             SensorHandle.ReportCapture(dxRootPath, SensorSpatialData.FromGameObjects(

com.unity.perception/Tests/Runtime/GroundTruthTests/DatasetJsonUtilityTests.cs

         [TestCase(1u, "1")]
         [TestCase(1.0, "1")]
         [TestCase(1.0f, "1")]
-        [TestCase("string", "\"string\"")]
+        [TestCase("string", "string")]
         public void Primitive_ReturnsValue(object o, string jsonExpected)
         {
             var jsonActual = DatasetJsonUtility.ToJToken(o).ToString();