All valid licenses permit security, and the only license state where
we don't support security is when there is a missing license.
However, for safety we should attach the system (or xpack/security)
user to internally originated actions even if the license is missing
(or, more strictly, doesn't support security).
This allows all nodes to communicate and send internal actions (shard
state, handshake/pings, etc) even if a license is transitioning
between a broken state and a valid state.
Relates: #42215
Backport of: #43468