Fix typo in spec description

Co-authored-by: Gaetan Craig-Riou <40413322+rioug@users.noreply.github.com>

engines/dfc_provider/spec/services/supplied_product_builder_spec.rb

@@ -255,7 +255,7 @@ describe SuppliedProductBuilder do
         end
       end
 
-      context "when doesn't spree_product_uri match the server host" do
+      context "when spree_product_uri doesn't match the server host" do
         let(:supplied_product) do
           DfcProvider::SuppliedProduct.new(
             "https://example.net/tomato",