Scylla returns the wrong error code (0000 - server internal error)
in response to trying to do authentication/authorization operations
that involves a non-existing role.
This commit changes those cases to return error code 2200 (invalid
query) which is the correct one and also the one that Cassandra
returns.
Tests:
Unit tests (Dev)
All auth and auth_role dtests
(cherry picked from commit ce8cebe34801f0ef0e327a32f37442b513ffc214)
Fixes#6363.
a3eb12c5f1