fix(qna): fix redirection and incorrect message

[asashour]

The points covered:

1. A flow or node can currently be invalidated after the Q&A item creation, if they are deleted in Flow dialog, this would make the Q&A item has "incorrect redirection". This PR shows them with an error in the item list, and doesn't allow saving unless they are both fine.
2. "Missing translations" in Editor/index.tsx was changed when the answers are empty only when isText, in other words, test case:
   a. Create an item with a single question, no answer, but a redirection
   b. Save it
   c. Open it, you will get an error, "missing translations"
3. Logic in item list was changed to follow the one in point 2
4. Flow name in item list is now user-friendly
5. The save button was renamed to Add/Save instead of Save/Edit
6. Full test of "missing translations" wasn't done because of lack of PRO license
7. Lite view wasn't tested, because I don't know how, so the "flows" was marked optional

[allardy]

All good ! Thank you ! The lite editor is only used by a new branch in active development, so we'll test it when we get there