I am not sure if acting on this warning will solve the issue you're having (i.e. not seeing any information in the Analytics admin site).
Anyway, here is what you should add to AndroidManifest.xml inside the application tag if you want to get rid of this warning:
<!-- Optionally, register AnalyticsReceiver and AnalyticsService to support background
dispatching on non-Google Play devices -->
<receiver android:name="com.google.android.gms.analytics.AnalyticsReceiver"
android:enabled="true">
<intent-filter>
<action android:name="com.google.android.gms.analytics.ANALYTICS_DISPATCH" />
</intent-filter>
</receiver>
<service android:name="com.google.android.gms.analytics.AnalyticsService"
android:enabled="true"
android:exported="false"/>
<!-- Optionally, register CampaignTrackingReceiver and CampaignTrackingService to enable
installation campaign reporting -->
<receiver android:name="com.google.android.gms.analytics.CampaignTrackingReceiver"
android:exported="true">
<intent-filter>
<action android:name="com.android.vending.INSTALL_REFERRER" />
</intent-filter>
</receiver>
<service android:name="com.google.android.gms.analytics.CampaignTrackingService" />
You don't have to add all of this, just add what you need. In your case, you apparently just need to add the AnalyticsService
service.
Source: https://developer.android.com/reference/com/google/android/gms/analytics/GoogleAnalytics.html