fix: ensure clicking field opens to field editor

[mantariksh]

Problem

Previously, when the builder drawer was closed, clicking on a
form field would open the drawer to the field list instead of
directly to the editing page for that field. This was because
of a useEffect which set fields to inactive whenever the active
tab changed.

Instead, we want to set the fields to inactive only when the active
tab is not the builder.

Solution

Check that the currently active tab isn't the Build tab before setting
fields to inactive.

Before

After