Fix type-hints for top-level conversion function imports

[ryanhill1]

When qasm3_to_qir and cirq_to_qir are imported directly from top-level qbraid_qir module, type-hints is not supported.

However, when those same functions are instead imported from their respected qbraid_qir.qasm3 and qbraid_qir.cirq sub-modules, type-hints are supported.

There should be a way to modify the lazy loading of these functions in qbraid_qir.__init__.py to support the type-hinting.