Automatic merge from submit-queue (batch tested with PRs 40746, 41699, 42108, 42174, 42093)
Avoid fake node names in user info
Node usernames should follow the format `system:node:<node-name>`,
but if we don't know the node name, it's worse to put a fake one in.
In the future, we plan to have a dedicated node authorizer, which would
start rejecting requests from a user with a bogus node name like this.
The right approach is to either mint correct credentials per node, or use node bootstrapping so it requests a correct client certificate itself.
dac0296f0b