[Form validation] Wrong radio behavior

[kevinresol]

As mentioned in this comment.

The code reads:

• if the result value is not set, set it to (isChecked) ? true : false

Two problems here

1. since the code will set the value if it is not set, so everything is only relevant in the first iteration
2. the ternary operation is meaningless, isChecked is already the boolean

But the bigger problem is that, it doesn't tell which radio box is checked.
Before that particular commit, the field obj returned should hold the value (.val()) of the checked radio box. After that, however, the value is a boolean which is the checked state of the first radio in the group.

[kevinresol]

Sorry, duplicate of #5713