This adds a new Skip input to the Simulation Output node (design task: #112082).
It is a convenience feature that makes it easy to conditionally forward the
output of the Simulation Input node to the Simulation Output node, without the
need for potentially multiple Switch nodes. When Skip is enabled, the other inputs
of the Simulation Output node are not evaluated, i.e. the nodes in the simulation
zone are ignored.
The implementation adds this new functionality directly to the `LazyFunction`
of the Simulation Output node. It has new inputs that are linked directly
to the Simulation Input node, so that the simulation state can be forwarded.
Pull Request: https://projects.blender.org/blender/blender/pulls/112140