Add support for XML data type in MSSQL by treating it as string

Co-authored-by: JerryNixon <1749983+JerryNixon@users.noreply.github.com>

Author: Copilot

src/Core/Models/SqlTypeConstants.cs

@@ -42,7 +42,7 @@ public static class SqlTypeConstants
         { "varbinary", true },            // SqlDbType.VarBinary
         { "varchar", true },              // SqlDbType.VarChar
         { "sql_variant", false },         // SqlDbType.Variant (unsupported)
-        { "xml", false },                 // SqlDbType.Xml (unsupported)
+        { "xml", true },                  // SqlDbType.Xml
         { "date", true },                 // SqlDbType.Date
         { "time", true },                 // SqlDbType.Time
         { "datetime2", true },            // SqlDbType.DateTime2

src/Core/Services/TypeHelper.cs

@@ -111,7 +111,8 @@ public static class TypeHelper
             [SqlDbType.TinyInt] = typeof(byte),
             [SqlDbType.UniqueIdentifier] = typeof(Guid),
             [SqlDbType.VarBinary] = typeof(byte[]),
-            [SqlDbType.VarChar] = typeof(string)
+            [SqlDbType.VarChar] = typeof(string),
+            [SqlDbType.Xml] = typeof(string)
         };
 
         private static Dictionary<SqlDbType, DbType> _sqlDbDateTimeTypeToDbType = new()