scaffolder: fix use of path.join in fetch:template tests

Signed-off-by: Mike Lewis <mtlewis@users.noreply.github.com>

plugins/scaffolder-backend/src/scaffolder/actions/builtin/fetch/template.test.ts

@@ -48,9 +48,7 @@ describe('fetch:template', () => {
     ActionContext<FetchTemplateInput>['createTemporaryDirectory']
   > = jest.fn(() =>
     Promise.resolve(
-      joinPath(
-        `${workspacePath}/${createTemporaryDirectory.mock.calls.length}`,
-      ),
+      joinPath(workspacePath, `${createTemporaryDirectory.mock.calls.length}`),
     ),
   );