title: Unity firebase notifications custom image
body: <p>I have decided to implement Firebase notifications into my unity project. The issue is that for notifications I want to use custom image, but that image is also used as app image (app_icon). I tried to modify manifest where I put into MessagingUnityPlayerActivity activity custom notification image (notificon) for displaying notification icon. </p>
  
  <pre><code>&lt;?xml version="1.0" encoding="utf-8"?&gt;
  &lt;manifest xmlns:android="http://schemas.android.com/apk/res/android"
            package="${applicationId}"
            android:versionCode="1"
            android:versionName="1.0"&gt;
    &lt;application android:label="@string/app_name"
                 android:icon="@drawable/app_icon"&gt;
      &lt;!-- The MessagingUnityPlayerActivity is a class that extends
           UnityPlayerActivity to work around a known issue when receiving
           notification data payloads in the background. --&gt;
      &lt;activity android:name="com.google.firebase.MessagingUnityPlayerActivity"
                android:label="@string/app_name"
                android:icon="@drawable/notificon"
                android:configChanges="fontScale|keyboard|keyboardHidden|locale|mnc|mcc|navigation|orientation|screenLayout|screenSize|smallestScreenSize|uiMode|touchscreen"&gt;
        &lt;intent-filter&gt;
          &lt;action android:name="android.intent.action.MAIN" /&gt;
          &lt;category android:name="android.intent.category.LAUNCHER" /&gt;
        &lt;/intent-filter&gt;
        &lt;meta-data android:name="unityplayer.UnityActivity" android:value="true" /&gt;
      &lt;/activity&gt;
      &lt;service android:name="com.google.firebase.messaging.MessageForwardingService"
               android:exported="false"/&gt;
    &lt;/application&gt;
  
  &lt;/manifest&gt;
  </code></pre>
  
  <p>I tried to modify it and delete some tags, but then the build wond compile. I should also mention that I have multiple manifests in my project and tried them to merge together but unsuccessfully. But this shouldnt be the problem since this is the only manifest with android:icon propery.</p>
  
  <p>Thank you</p>