Small overview page issues

The beta NOMAD runs now a relase candidate for v0.10.0. I was just looking through the first few entries (overall, first geometry opt, first bandstructure). There are still a few issues that we should address quickly:

• its a pretty simply system, but could not be shown. Shows up in encyclopedia though: https://nomad-lab.eu/prod/rae/beta/gui/entry/id/F0rCHPUqSXuUfjGHTQF2Rg/WzW3n_6B95ZIW-CfAuXbH4vj41Qr/overview

Caused by issue in detecting empty simulation cells, now fixed.

• the warning should be less severe (no red) and without paper: https://nomad-lab.eu/prod/rae/beta/gui/entry/id/Epga6zVpShWpkMjypG7mMA/-QYrcSVCS9OGwFDjdhL941ZM0NiZ

  Now the message is using the Alert-component from MUI with severity="info".

• this is not showing a geometry opt, but everything seems to be there: https://nomad-lab.eu/prod/rae/beta/gui/entry/id/10k9kKRNTiWFsaK56Ft3og/-4oK7xt-I9sbkL7684cpd4v5TrS_/overview

  One of the SCCs belonging to the optimization trajectory is missing the energy and a reference to the structure. I posted a new parser issue about this (#506 (closed)). Now an error is raised instead of failing silently.

• this looks like a bug. Even if the error is show, there should be no paper on paper: https://nomad-lab.eu/prod/rae/beta/gui/entry/id/EMtbEy_XQ9aPZjJYRMJtDA/1HSP0tidKfWRUl0Xi76kkxYqyIgr

  This is related to issue #440 (closed). The errors are shown individually for the band structure and Brillouin zone, because the data for both is missing. It looks a bit awkward, but I think the errors should be separate, as just only one of them can be broken/missing. Now the error messages use the Alert-component from MUI.