Submission Form - Reording items and changing their values is inconsistent

[AndreaBarbasso]

Describe the bug

This bug report is an extension of #3217. Reordering items via drag-and-drop and changing their values may lead to incoherent outcomes.

To Reproduce

Steps to reproduce the behavior:

1. Log into the sandbox, then add a new Book item;
2. Go to the Type section, add three or more types;
3. Scramble them via drag and drop, then save. You will see that the items are saved in another order;
4. Then, switch the position of two items and change one of them. The other item also changes, but if you save again you will see other inconsistencies.

Video demonstration:

reordering-sandbox.mp4

Expected behavior

Reordering and changing values should be coherent and consistent, and the saved values should reflect the ones shown on the UI.

Related work

#3217