Form required value update for non required field types.

[Skullfox]

Q	A
Bug?	Yes
New Feature?	no
Bundle Version	2.5.0
Sulu Version	2.5.1

Actual Behavior

Changing a form field with checked required checkbox to any other field type like free text, with no required checkbox, dont update the required property after saving.

Steps to Reproduce

Create new form field with checked required and save.

Change field to Free Text and save.

The form field now still contains the required property with true which breaks the form.

[hxrriet02]

I'm having the same issue. The error on the client side on submit is quite unclear too which field it is, just saying 'This value should not be blank.'.