[interactive_media_ads] Fixes AdEventTypes not triggering on iOS in release mode (#8918)

Because `_delegate` was an unused field, Dart would garbage collect the value in release mode. To prevent this, this adds the `@pragma('vm:entry-point')` to indicate that the value is an entry point for the platform side. See the comment above the field.

Fixes flutter/flutter#163049

## Pre-Review Checklist

[^1]: Regular contributors who have demonstrated familiarity with the repository guidelines only need to comment if the PR is not auto-exempted by repo tooling.

Author: bparrishMines

packages/interactive_media_ads/CHANGELOG.md

@@ -1,3 +1,7 @@
+## 0.2.3+10
+
+* Fixes `AdEventType`s not triggering on iOS in release mode.
+
 ## 0.2.3+9
 
 * Bumps gradle from 8.0.0 to 8.9.0.

packages/interactive_media_ads/android/src/main/kotlin/dev/flutter/packages/interactive_media_ads/AdsRequestProxyApi.kt

@@ -21,7 +21,7 @@ class AdsRequestProxyApi(override val pigeonRegistrar: ProxyApiRegistrar) :
      *
      * This must match the version in pubspec.yaml.
      */
-    const val pluginVersion = "0.2.3+9"
+    const val pluginVersion = "0.2.3+10"
   }
 
   override fun setAdTagUrl(pigeon_instance: AdsRequest, adTagUrl: String) {

packages/interactive_media_ads/ios/interactive_media_ads/Sources/interactive_media_ads/AdsRequestProxyAPIDelegate.swift

@@ -13,7 +13,7 @@ class AdsRequestProxyAPIDelegate: PigeonApiDelegateIMAAdsRequest {
   /// The current version of the `interactive_media_ads` plugin.
   ///
   /// This must match the version in pubspec.yaml.
-  static let pluginVersion = "0.2.3+9"
+  static let pluginVersion = "0.2.3+10"
 
   func pigeonDefaultConstructor(
     pigeonApi: PigeonApiIMAAdsRequest, adTagUrl: String, adDisplayContainer: IMAAdDisplayContainer,

packages/interactive_media_ads/lib/src/ios/ios_ads_manager.dart

@@ -22,6 +22,7 @@ class IOSAdsManager extends PlatformAdsManager {
   // This must maintain a reference to the delegate because the native
   // `IMAAdsManagerDelegate.delegate` property is only a weak reference.
   // Therefore, this would be garbage collected without this explicit reference.
+  @pragma('vm:entry-point')
   // ignore: unused_field
   late IOSAdsManagerDelegate _delegate;
 

packages/interactive_media_ads/pubspec.yaml

@@ -2,7 +2,7 @@ name: interactive_media_ads
 description: A Flutter plugin for using the Interactive Media Ads SDKs on Android and iOS.
 repository: https://github.com/flutter/packages/tree/main/packages/interactive_media_ads
 issue_tracker: https://github.com/flutter/flutter/issues?q=is%3Aissue+is%3Aopen+label%3A%22p%3A+interactive_media_ads%22
-version: 0.2.3+9 # This must match the version in
+version: 0.2.3+10 # This must match the version in
   # `android/src/main/kotlin/dev/flutter/packages/interactive_media_ads/AdsRequestProxyApi.kt` and
   # `ios/interactive_media_ads/Sources/interactive_media_ads/AdsRequestProxyAPIDelegate.swift`