refactor(tests): update viewport page object usage to async and update all effected tests (#5927)

tests/Spline.spec.ts

@@ -13,7 +13,8 @@ test('should display the spline tool', async ({
   viewportPageObject,
 }) => {
   await mainToolbarPageObject.measurementTools.splineROI.click();
-  await viewportPageObject.active.clickAt([
+  const activeViewport = await viewportPageObject.active;
+  await activeViewport.clickAt([
     { x: 380, y: 459 },
     { x: 420, y: 396 },
     { x: 523, y: 392 },