Resolve "E2E tests are failing for one month"

Closes #678 (closed)

e2e/ouvrages-empty-fields.e2e-spec.ts

@@ -123,6 +123,7 @@ describe("ngHyd - check that created/cloned structures have empty fields - ", ()
 
         // copy structure
         const addStruct = await calcPage.getCopyStructureButton();
+        await addStruct.waitForClickable({ timeout: 5000 });
         await addStruct.click();
         await browser.pause(200);
 
@@ -161,6 +162,7 @@ describe("ngHyd - check that created/cloned structures have empty fields - ", ()
 
         // copy structure
         const addStruct = await calcPage.getAddStructureButton();
+        await addStruct.waitForClickable({ timeout: 5000 });
         await addStruct.click();
         await browser.pause(200);