Tests should generate the wheel and then use it to install for the tests

[ianhi]

This will better emulate then end user experience, as well as detect any issue with the build.

For example on ipywidgets the tests are run by installing the previously generated file:
https://github.com/jupyter-widgets/ipywidgets/blob/61e8887fa0523c6b861a4fc6b2467678c5d699e5/.github/workflows/tests.yml#L115-L118