Incorrect check if experiment data is compatible about qiskit-experiments

[ishworii]

Can I work on this?

[yaelbh]

I fixed it in #62, but would like to get @chriseclectic's approval that it's correct

[merav-aharoni]

I think the assertion itself is correct. We should set the experiment_type in runwhen experiment_data is None, as follows:

            # Create new experiment data
            experiment_data = self.__experiment_data__(experiment=self, backend=backend)
            experiment_data.metadata()["experiment_data"] = self._type

I did this when I failed in #PR91 and it works fine.
In addition, I think there is no reason to set the experiment_type in every circuit.

[chriseclectic]

The data container already has the type as a property so this check should be experiment_data.experiment_type == self._type

[merav-aharoni]

Is someone making this fix? because my tests are failing on this bug. If no one is doing it, I can open a separate PR on this and get it done.

[yaelbh]

You can do it. I did it in #62 to solve the problem there, but I don't know when it will be ready, and separating PRs is always good.