fix(UIManager): 修复UI表单释放时使用ContainsKey替代Contains的问题

修改m_UIFormsToReleaseOnLoad的检查方式从Contains到ContainsKey以正确匹配字典类型
优化释放逻辑，提前获取表单引用避免重复调用GetUIForm

Author: AlianBlank

Runtime/UIManager.Open.cs

@@ -128,7 +128,7 @@ private IUIForm InternalOpenUIForm(int serialId, string uiFormAssetName, Type ui
                 var uiGroup = uiForm.UIGroup;
                 if (serialId < 0)
                 {
-                    if (m_UIFormsToReleaseOnLoad.Contains(uiForm.SerialId))
+                    if (m_UIFormsToReleaseOnLoad.ContainsKey(uiForm.SerialId))
                     {
                         m_UIFormsToReleaseOnLoad.Remove(uiForm.SerialId);
                     }
@@ -192,12 +192,13 @@ private IUIForm LoadAssetSuccessCallback(string uiFormAssetName, object uiFormAs
             }
 
 
-            if (m_UIFormsToReleaseOnLoad.Contains(openUIFormInfo.SerialId))
+            if (m_UIFormsToReleaseOnLoad.ContainsKey(openUIFormInfo.SerialId))
             {
                 m_UIFormsToReleaseOnLoad.Remove(openUIFormInfo.SerialId);
+                var form = GetUIForm(openUIFormInfo.SerialId);
                 ReferencePool.Release(openUIFormInfo);
                 m_UIFormHelper.ReleaseUIForm(uiFormAsset, null);
-                return GetUIForm(openUIFormInfo.SerialId);
+                return form;
             }
 
             m_UIFormsBeingLoaded.Remove(openUIFormInfo.SerialId);
@@ -218,10 +219,11 @@ private IUIForm LoadAssetFailureCallback(string uiFormAssetName, string errorMes
                 throw new GameFrameworkException("Open UI form info is invalid.");
             }
 
-            if (m_UIFormsToReleaseOnLoad.Contains(openUIFormInfo.SerialId))
+            if (m_UIFormsToReleaseOnLoad.ContainsKey(openUIFormInfo.SerialId))
             {
                 m_UIFormsToReleaseOnLoad.Remove(openUIFormInfo.SerialId);
-                return GetUIForm(openUIFormInfo.SerialId);
+                var uiForm = GetUIForm(openUIFormInfo.SerialId);
+                return uiForm;
             }
 
             m_UIFormsBeingLoaded.Remove(openUIFormInfo.SerialId);