feature request - noise injection during middle of upscale or time step control

[EricRollei]

Noise injection in the middle of the steps is a great way to add more details. For example see the section in Matteos upscaling graph where he splits the sampling into two nodes and injects noise in the middle.

For Ultimate Upscaling, an ideal implementation would be to just have a switch to turn on the inject noise, and a slider for how much noise, and maybe an int input for the step to inject the noise, but I don't know if that's easy to do. Start at step and end at step could be easier?

Thank you for these nodes, they are great.