refactor(ecstore): migrate audit KVS defaults to shared constructors
The amqp, nats, pulsar, redis, postgres, kafka and mysql default KVS tables in config/audit.rs duplicated the corresponding tables in config/notify.rs, leaving seven cross-file sync points where a default could silently drift between the two subsystems. Build them from the shared constructors added in config/target_defaults.rs instead, passing in the two literals that are genuinely audit-specific: the redis pub/sub channel (AUDIT_REDIS_DEFAULT_CHANNEL) and the mysql destination table ("rustfs_audit_logs").
Key order, every default value and every hidden_if_empty flag are preserved exactly, since the key order drives the order admin config output lists keys in. DEFAULT_AUDIT_WEBHOOK_KVS and DEFAULT_AUDIT_MQTT_KVS are left untouched: those two tables really do differ from their notify counterparts, so unifying them would change runtime behavior.
Refs rustfs/backlog#2045
(cherry picked from commit 4de580e6d8901485eef268191924e035322d4d4e)
(cherry picked from commit e5e301fa78e7f27ffa85b05cf5e7962301a5ff00)
Zhengchao An
75e605fe87