Creating ensembes/experiments with unique names is not consistent

[oyvindeide]

In some places in the ert gui we have enforced that experiment names and ensembles must be unique, but that is not always enforced, as it is possible to make a new experiment in Experiment manager with a duplicate name. This is mostly not a problem, but will make it hard to tell the difference when plotting for example, or doing restart of es-mda.

• Show experiment name in plotter #7892
• Use UUID for ensembles internally instead of `get_ensemble_by_name´ #7893
• Evaluate ensemble does not always autopopulate active realizations #7895
• Ensemble name unique validation not working as expected #7913

[oyvindeide]

Completed!