website: Add e2e tests of creating an assistant/prompter reply

These are intended to function as a minimal smoke test that the API interaction with the backend is functional.

website/src/components/TaskInfo/TaskInfo.tsx

@@ -2,7 +2,7 @@ export const TaskInfo = ({ id, output }: { id: string; output: string }) => {
   return (
     <div className="grid grid-cols-[min-content_auto] gap-x-2 text-gray-700">
       <b>Prompt</b>
-      <span>{id}</span>
+      <span data-cy="task-id">{id}</span>
       <b>Output</b>
       <span>{output}</span>
     </div>