chore: upgrade sdk to build.4 for windows (#2392)

Author: peilinok

pubspec.yaml

@@ -2,7 +2,7 @@ name: agora_rtc_engine
 description: >-
   Flutter plugin of Agora RTC SDK, allow you to simply integrate Agora Video
   Calling or Live Video Streaming to your app with just a few lines of code.
-version: 6.2.6-sp.426164.b.4
+version: 6.2.6-sp.426164.b.5
 homepage: https://www.agora.io
 repository: https://github.com/AgoraIO-Extensions/Agora-Flutter-SDK/tree/main
 environment:

windows/CMakeLists.txt

@@ -12,8 +12,8 @@ project(${PROJECT_NAME} LANGUAGES CXX)
 # not be changed
 set(PLUGIN_NAME "agora_rtc_engine_plugin")
 
-set(IRIS_SDK_DOWNLOAD_URL "https://download.agora.io/sdk/release/iris_4.2.6.164-build.3_DCG_Windows_Video_20250715_0950.zip")
-set(IRIS_SDK_DOWNLOAD_NAME "iris_4.2.6.164-build.3_DCG_Windows")
+set(IRIS_SDK_DOWNLOAD_URL "https://download.agora.io/sdk/release/iris_4.2.6.164-build.4_DCG_Windows_Video_20250719_0619.zip")
+set(IRIS_SDK_DOWNLOAD_NAME "iris_4.2.6.164-build.4_DCG_Windows")
 set(RTC_SDK_DOWNLOAD_NAME "Agora_Native_SDK_for_Windows_FULL")
 set(IRIS_SDK_VERSION "v3_6_2_fix.1")