The 'New Image Style' input field's border from Administration is red as if a condition has not been met as the user lands on the page

Steps to reproduce

1. Login as Admin
2. Go to Administer Wiki > Look & Feel > Image Styles
3. Observe the 'New Image Style' input field's border

Expected results

The 'New Image Style' input field's border is neutral (grey).

Since the "Create the image style" button is greyed out, a (mandatory) value cannot be expected to be already inserted as soon as the user lands on the page.

Actual results

The 'New Image Style' input field's border is red, as if it expects a mandatory value (or a non-compliant value was already entered) as soon as the user lands on the page.

The red border check should be displayed only if a condition is not met, but as far as I can understand the "Create the image style" button is greyed out now if nothing is inserted in the field.

The issue was not present in XWiki 14.10.16, but the "Create the image style" button was not greyed out either.