Move qiskit-aer and qiskit-ibm-runtime to test deps

[jpopesculian]

No description provided.

[CLAassistant]

All committers have signed the CLA.

[garrison]

Thank you for the PR.

The reason I haven't removed aer yet as a dependency is explained in my comment at #148 (comment). (I could elaborate on this, if it would be helpful, and I should double check that it is still accurate.) I see no issue with removing qiskit-ibm-runtime as a direct dependency. And the hesitation about removing aer as a dependency is really due to a quirk in the design of qiskit-ibm-runtime.

In order to remove both, I'd like to know that the notebook tests run with or without aer installed. I'd be willing to help configure tox.ini to enable this if we can first demonstrate it to be the case.

These packages will also need to be added to the notebook-dependencies, and this deserves a release note once we decide the path forward.