This removes the need for a lot of HasValue checks, especially since all fields will eventually get a value anyway, making those checks rather redundant. This also makes it clearer that all SRVs will get bound with a valid input texture, even if the input is optional.
This eliminates the need for resource binding code outside of the core FSR2 classes, and makes the public API more strict and consistent. It also removes the need for the slightly awkward input/output resource debug checks.