Treat null/missing CmpContext and IsMasterPage as equivalent in GetGxObject

HttpAjaxContext.GetGxObject(JArray, CmpContext, IsMasterPage) iterates the
array looking for an entry that matches the (CmpContext, IsMasterPage)
pair. The previous lookup called obj['CmpContext'].ToString() and
obj['IsMasterPage'].ToString() directly — when the array entry didn't
carry those keys, the indexer returned null and ToString() threw
NullReferenceException, which fell into the catch and made the function
return null, breaking the callers (ajax_rsp_assign_attri and similar).

Make the comparison null-safe and treat 'missing/null/empty' as
semantically equivalent to the default value:
- CmpContext: a missing/empty entry matches a null-or-empty parameter.
- IsMasterPage: a missing/empty entry matches IsMasterPage == false
  (default for bool). Comparison is case-insensitive against
  IsMasterPage.ToString().

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>
(cherry picked from commit 883f4bb)

# Conflicts:
#	dotnet/src/dotnetframework/GxClasses/Core/Web/HttpAjaxContext.cs

Author: claudiamurialdo

dotnet/src/dotnetframework/GxClasses/Core/Web/HttpAjaxContext.cs

@@ -279,41 +279,38 @@ public void ajax_rspEndCmp()
 		}
 
 		private JObject GetGxObject(JArray array, String CmpContext, bool IsMasterPage)
-        {
-            try
-            {
-                JObject obj;
+		{
+			try
+			{
+				JObject obj;
+				string paramCmpContext = CmpContext ?? string.Empty;
+				string paramIsMasterPage = IsMasterPage.ToString();
+
 				for (int i = 0; i < array.Count; i++)
-                {
+				{
 					obj = array.GetObject(i);
-					string objCmpContext = obj["CmpContext"]?.ToString();
-					string objIsMasterPage = obj["IsMasterPage"]?.ToString();
-					// A missing/null/empty CmpContext on the array entry is equivalent to a null-or-empty parameter.
-					bool cmpContextMatches = string.IsNullOrEmpty(objCmpContext)
-						? string.IsNullOrEmpty(CmpContext)
-						: objCmpContext.Equals(CmpContext);
-					// A missing IsMasterPage on the array entry is treated as the default value (false).
-					bool isMasterPageMatches = string.IsNullOrEmpty(objIsMasterPage)
-						? !IsMasterPage
-						: objIsMasterPage.Equals(IsMasterPage.ToString(), StringComparison.OrdinalIgnoreCase);
-					if (cmpContextMatches && isMasterPageMatches)
-                    {
-                        return obj;
-                    }
-                }
-                obj = new JObject();
-                obj.Put("CmpContext", CmpContext);
-                obj.Put("IsMasterPage", IsMasterPage.ToString());
+					string objCmpContext = obj["CmpContext"]?.ToString() ?? string.Empty;
+					string objIsMasterPage = obj["IsMasterPage"]?.ToString() ?? string.Empty;
+
+					if (objCmpContext.Equals(paramCmpContext) && objIsMasterPage.Equals(paramIsMasterPage))
+					{
+						return obj;
+					}
+				}
+
+				obj = new JObject();
+				obj.Put("CmpContext", CmpContext);
+				obj.Put("IsMasterPage", IsMasterPage.ToString());
 				array.Add(obj);
-                return obj;
-            }
+				return obj;
+			}
 			catch (Exception ex)
 			{
 				GXLogging.Error(log, "GetGxObject error", ex);
 			}
 
 			return null;
-        }
+		}
 
         public void ajax_rsp_assign_attri(String CmpContext, bool IsMasterPage, String AttName, Object AttValue)
 		{