[pallas:fuser] Support full-dimension (dynamic_)slice and (dynamic_)update_slice

with non-multiple block sizes.

Support (dynamic_)slice and (dynamic_)update_slice output fusion when tensor
dimensions are not multiples of the block size, provided the slice/update
spans the full dimension (i.e. full_size == slice_size).

PiperOrigin-RevId: 972810803