test: test for actual validation string, not the validation lookup

spec/models/scheme_spec.rb

@@ -217,7 +217,7 @@ RSpec.describe Scheme, type: :model do
 
     context "when the owning organisation is set as a non-stock-owning organisation" do
       it "throws the correct validation error" do
-        expect { scheme.update!({ owning_organisation_id: non_stock_owning_org.id }) }.to raise_error(ActiveRecord::RecordInvalid, /#{I18n.t("validations.scheme.owning_organisation.does_not_own_stock")}/)
+        expect { scheme.update!({ owning_organisation_id: non_stock_owning_org.id }) }.to raise_error(ActiveRecord::RecordInvalid, /Enter an organisation that owns housing stock/)
       end
     end
   end

spec/requests/schemes_controller_spec.rb

@@ -611,7 +611,7 @@ RSpec.describe SchemesController, type: :request do
         it "displays the new page with an error message" do
           post "/schemes", params: params
           expect(response).to have_http_status(:unprocessable_entity)
-          expect(page).to have_content(I18n.t("validations.scheme.owning_organisation.does_not_own_stock"))
+          expect(page).to have_content("Enter an organisation that owns housing stock")
         end
       end
     end