When changing forms while keeping the fields (that ALT trick), update the form information on each field

[rafaehlers]

When switching the form used as the View data source using the ALT trick to keep the existing fields, the field information needs to be updated to reflect the new form.

Here's a video explaining this: https://www.loom.com/share/9d807b001a8c40f5b9d4b892a690e6eb

Steps to reproduce

1. Access the View editor
2. Hold the ALT key on your keyboard while clicking on the data source dropdown to pick a new form
3. Select a new form
4. Save the View
5. Check the field settings modal

What's expected

After switching forms and saving the View, the form information on each field gets updated.

ps.: This issue was originally branched out from this other one: #2159