This fixes a regression introduced with a1afeded6ae63e47d39fc08480e929c0451c51e8.
The connections were setup every the windowShown signal got emitted.
This caused effects to get multiple singals and start multiple animations
which then do not get cancelled correctly.
The incorrect behavior was most visible in the translucency effect which
did not cancel the move animation and the window stayed translucent.
BUG: 366081