Received some memory metrics regression during landing the #82670 . Related to #88480 .

We introduced the DualTransitionBuilder internally in #58686 and it's only for the zoom page transition currently. When there are two routes interacting in the tree, we'll get at least two sealed transitions including 2 scales and 2 fades plus 1 opacity transforms. Although some part of them won't triggered during the enter/exit action, it might address some memory metrics increased.

A potential solution is to roll back with two AnimationBuilders, not sure if it'll break original tests or not.

/cc @goderbauer @shihaohong