Allow type change for static columns in CsvDataReader

Added logic to enable changing the DataType of static columns when setting a column type by name. Previously, only dynamic columns could have their type changed; now static columns are also supported.

Author: potatoqualitee

project/dbatools/Csv/Reader/CsvDataReader.cs

@@ -3528,6 +3528,17 @@ public void SetColumnType(string columnName, Type type)
                     return;
                 }
             }
+
+            // Also check static columns - they already have a type set, but allow changing it
+            for (int i = 0; i < _staticColumns.Count; i++)
+            {
+                if (string.Equals(_staticColumns[i].Name, columnName, StringComparison.OrdinalIgnoreCase))
+                {
+                    _staticColumns[i].DataType = type;
+                    return;
+                }
+            }
+
             throw new ArgumentException($"Column '{columnName}' not found", nameof(columnName));
         }