Change KSampler add_noise type to BOOLEAN (improvement)

KSampler Advanced has an `add_noise` field whose value is either `enable` or `disable`. However, it's neither a boolean nor a string, making it harder to control outside of the node itself.

Considering it doesn't have any reason not to be a boolean I think it should be changed to the proper native type. Same goes for `return_with_leftover_noise` or any other field: do not use a custom data type if a native type is enough.

Locate the KSampler Advanced node definition and inspect how its add_noise and return_with_leftover_noise fields are declared and consumed. Check the surrounding node input schema and call sites first; done means these fields use native boolean values while preserving their existing behavior, with any additional custom types considered separately.

Written by the indexing model from the issue text.