The "fix" is straightforward -- callers of system_keyspace::*paxos* methods need to get system keyspace from somewhere. This time the only caller is storage_proxy::remote that can have system keyspace via direct dependency reference.
Closes#14758
* github.com:scylladb/scylladb:
db/system_keyspace: Move and use qctx::execute_cql_with_timeout()
db/system_keyspace: Make paxos methods non-static
service/paxos: Add db::system_keyspace& argument to some methods
test: Optionally initialize proxy remote for cql_test_env
proxy/remote: Keep sharded<db::system_keyspace>& dependency