Allow set-siteconfig to set nonexisting keys.
Review Request #12596 — Created Sept. 13, 2022 and submitted
One annoying thing about the
set-siteconfigmanagement command is that
it would error out if you tried to set a key that wasn't already
explicitly set, even if a default was defined.
This change fixes that to allow setting those. We still do validation on
the "parent" keys when a setting path is drilling down into dicts, but
any leaf key can now be set.
Saw that I could now set items in siteconfig that I couldn't before.
I'm not sure how this works. If it's a new key, we get a NoneType. That will later crash when …