When writing VFS, it initally seemed useful to include a function to in-place convert container files into directories in one homogenous directory structure, but re-evaluating it now there have been plenty of chances to use it and there has always been a better way. Removing as it is unused and likely will not be used.
The only reason the getter existed was to check whether or not the
program NCA was null. Instead, we can just provide a function to query
for the existence of it, instead of exposing it entirely.
If any of the error paths before the NCA retrieval are taken, it'll
result in program_nca_status being left in an inconsistent state. So we
initialize it by default with a value indicating an error.
We can make the enum class type compatible with fmt by providing an
overload of operator<<.
While we're at it, perform proper bounds checking. If something exceeds
the array, it should be a hard fail, because it's, without a doubt, a
programmer error in this case.