feat: [SDK-5128] add explicit Android notification grouping to demos (#894)

Co-authored-by: Cursor Agent <cursoragent@cursor.com>
Co-authored-by: Fadi George <fadi-george@users.noreply.github.com>

Author: 3 people

examples/demo-no-location/Assets/Scripts/NoLocationDemo.cs

@@ -12,6 +12,7 @@ public sealed class NoLocationDemo : MonoBehaviour
     private string _oneSignalAppId = "YOUR-ONESIGNAL-APP-ID";
 
     private const float ReferenceWidth = 393f;
+    private const string DemoAndroidGroup = "demo-group";
     private static readonly Color _backgroundColor = new Color32(248, 249, 250, 255);
     private static readonly Color _primaryColor = new Color32(229, 75, 77, 255);
     private static readonly Color _valueColor = new Color32(47, 52, 55, 255);
@@ -342,7 +343,8 @@ private async Task<bool> PostTestNotification(string pushSubscriptionId)
             + $"\"app_id\":\"{_oneSignalAppId}\","
             + $"\"include_subscription_ids\":[\"{pushSubscriptionId}\"],"
             + "\"headings\":{\"en\":\"OneSignal No-Location Demo\"},"
-            + "\"contents\":{\"en\":\"This test push was sent without linking the location module.\"}"
+            + "\"contents\":{\"en\":\"This test push was sent without linking the location module.\"},"
+            + $"\"android_group\":\"{DemoAndroidGroup}\""
             + "}";
 
         using var request = new UnityWebRequest(

examples/demo/Assets/Scripts/Services/OneSignalApiService.cs

@@ -18,6 +18,8 @@ public class OneSignalApiService
 
         private const string DefaultAndroidChannelId = "b3b015d9-c050-4042-8548-dcc34aa44aa4";
 
+        private const string DemoAndroidGroup = "demo-group";
+
         public void SetAppId(string appId) => _appId = appId;
 
         public string GetAppId() => _appId;
@@ -178,6 +180,7 @@ private JObject BuildBasePayload(string title, string body, string subscriptionI
                 ["include_subscription_ids"] = new JArray(subscriptionId),
                 ["headings"] = new JObject { ["en"] = title },
                 ["contents"] = new JObject { ["en"] = body },
+                ["android_group"] = DemoAndroidGroup,
             };
 
         // Retry while the OneSignal backend hasn't yet indexed the freshly