修复 WebView3 拖拽选中内容时闪退 & 账号切换头像不显示 & 主进程判断不正确 & AbandonedMutexException

src/ST.Client.Mobile.iOS/UI/AppDelegate.cs

@@ -1,4 +1,4 @@
-using Foundation;
+using Foundation;
 using UIKit;
 using Xamarin.Forms;
 using Xamarin.Forms.Platform.iOS;
@@ -36,5 +36,10 @@ namespace System.Application.UI
 
             return base.FinishedLaunching(app, options);
         }
+
+        /// <summary>
+        /// 当前是否是主进程
+        /// </summary>
+        public static bool IsMainProcess { get; private set; }
     }
-}
+}