Fix handling of cargs in BasicQisVisitor

[jrj-d]

The unit tests in this commit fail without the change made to file src/qiskit_qir/visitor.py.

File ~/ab/demos/20230404/venv/lib/python3.9/site-packages/qiskit_qir/visitor.py:189, in <listcomp>(.0)
    187 for (inst, i_qargs, i_cargs) in subcircuit.data:
    188     mapped_qbits = [qargs[subcircuit.qubits.index(i)] for i in i_qargs]
--> 189     mapped_clbits = [cargs[subcircuit.clbits.index] for i in i_cargs]
    190     _log.debug(
    191         f"Processing sub-instruction {inst.name} with mapped qubits {mapped_qbits}")
    192     self.visit_instruction(inst, mapped_qbits, mapped_clbits)

TypeError: list indices must be integers or slices, not builtin_function_or_method

[jrj-d]

@microsoft-github-policy-service agree company="Alice & Bob"

[idavis]

Thanks for the PR @jrj-d! Would you mind re-signing the CLA without the company name for an individual contributions?

Options:
(default - no company specified) I have sole ownership of intellectual property rights to my Submissions and I am not making Submissions in the course of work for my employer.

@microsoft-github-policy-service agree

[idavis]

@jrj-d Following up. Happy to merge once we resolve the CLA check.

[jrj-d]

@microsoft-github-policy-service agree

[jrj-d]

Sorry I missed your message @idavis !