top: fix initial cursor position for fields management

top: fix initial cursor position for fields management

When we transitioned from 'char' based fields to 'int'
proper initial cursor positioning (highlight) was lost
in the 'fields_utility' function. The highlight should
appear on the current sort field. Instead, however, it
was often positioned on the first field listed or some
completely different field other than that sort field.

So this patch will restore the master branch behavior.

[ and on the assumption that a sort field is visible ]
[ we will search first for a field with the 'on' bit ]

Reference(s):
. Mar, 2022 - trade 'char' for 'int'
commit 46aa96e438435628810b33d20cb1c14dc33dd84f

Signed-off-by: Jim Warner <james.warner@comcast.net>