Merge branch 'master' into 'master'

Fix for enrollment app install without Google

See merge request entgra/carbon-device-mgt-plugins!121

components/mobile-plugins/android-plugin/org.wso2.carbon.device.mgt.mobile.android.api/src/main/java/org/wso2/carbon/mdm/services/android/util/AndroidDeviceUtils.java

@@ -711,7 +711,7 @@ public class AndroidDeviceUtils {
                 JsonElement googlePolicyPayload = appElement.getAsJsonObject().
                         get(AndroidConstants.ApplicationInstall.GOOGLE_POLICY_PAYLOAD);
 
-                if (googlePolicyPayload == null) {
+                if (googlePolicyPayload == null || googlePolicyPayload.toString().equals("\"\"")) {
                     uuid = appElement.getAsJsonObject().
                             get(AndroidConstants.ApplicationInstall.ENROLLMENT_APP_INSTALL_UUID).getAsString();
                     try (CloseableHttpClient httpClient = HttpClients.createDefault()) {