The purchase of weapons by other countries and the sale of Canadian weapons to other countries are not included in Canadian defence expenditures. As you said, they contribute to the GDP and, if they are NATO countries, they help those countries reach the 2% of GDP target recommended by NATO. If the countries are not NATO members and they have other obligations, those transactions might be included in their defence expenditures. So they are not included in Canada's defence expenditures.
On June 21st, 2022. See this statement in context.