unbreak about CPU value when solid is missing a product string

instead of Processors: 4 x one now gets Processors: 4, or Processors: 4 x Unknown Type, 12 x AMD Ryzen 5 3600X 6-Core Processor when some of the cores have a product and the others do not.

The latter is an incredible edge case but I suppose we best handle it properly. It did require reshuffling of the entry though. We now list the cores in the ctor to generate the label but only generate the values at call time so as to localize this potential placeholder accordingly.

Meanwhile the former case ultimately lumps all processors together even when they are actually different from a physical POV (such as the heterogenous CPU set up of "ARM big.LITTLE"), but given the high level overview this KCM provides there is no point in expansively trying to figure out what the actual topology is (we do indeed not concern ourselves with topology at all in this entry).

BUG: 439464 FIXED-IN: 5.22.4