Consider some paranoia post-load processing of Status.json

[Athanasius]

In #1393 one suspicion is that maybe sometimes Status.json has a BodyName key but with a '' value.

We should consider doing some sanity checking on what we load in dashboard.py:Dashboard.process().

1. Filter out any key where the value is an empty string ? Is this ever actually valid ?
2. If somehow a null/None value is in there, the same question
3. Do we definitely want to do this, given it potentially affects third-party plugins? Or maybe just define a utility function for the core plugins to utilise ?