CameraService: Enable presubmit unit tests, and fix them

- Add cameraservice_test to presubmit TEST_MAPPING
- Fix broken CameraProviderManager test

Test: Fixed test passes; 'atest' in frameworks/av/services/camera/libcameraservice
   runs the expected test

Change-Id: Ia1ceaf526884325d56f0e273f89220fdb33493dd
diff --git a/services/camera/libcameraservice/TEST_MAPPING b/services/camera/libcameraservice/TEST_MAPPING
new file mode 100644
index 0000000..6fdac68
--- /dev/null
+++ b/services/camera/libcameraservice/TEST_MAPPING
@@ -0,0 +1,7 @@
+{
+  "presubmit": [
+    {
+       "name": "cameraservice_test"
+    }
+  ]
+}