ResultDelegate: Fix height binding loop on multiline

This binding loop was making krunner freeze when the
text expanded more than 3 lines

We shouldn't be setting the `height` on an item based on their
childrens height. Luckily, the Layout automatically calculates
this for us

BUG: 454507
FIXED-IN: 5.24.6
(cherry picked from commit 19dc0f02)