Allow seed as a tensor-valued argument to sample

[ihincks]

Description

We should allow seed as a tensor-valued argument to sample with intrinsic shape (), that is, a scalar.
The reason for doing this is to allow downstream components (executor cough cough) to allow broadcasting semantics over the seed.

This will allow users to do things like this

quantum_program.append_samplex_item(
    template,
    samplex,
    samplex_arguments={seed: <1x20>, basis_changes.x: <9, 1>:})

in order to end up with 9 basis changes, but where the pauli randomizations are the same for each basis change.

Acceptance criteria

The seed is settable as a tensor-valued argument when invoking Samplex.sample().