Fix missing DB duration keys for multiple databases

What does this MR do and why?

Because of addition to support database_tasks: false (!82902 (merged)), we accidentally skipped the ci key, and stopped emitting DB duration / count metrics for logs.

Added specs for this regression

To reproduce

Open any page in development, and observe log/development_json.log, it should have db_ci_* keys.

On master:

{"method":"GET","path":"/","format":"html","controller":"RootController","action":"index","status":200,"time":"2022-04-21T23:44:42.441Z","params":[],"correlation_id":"01G1786TKQHM9Z94PPRGW92YP5","meta.user":"root","meta.client_id":"user/1","meta.caller_id":"RootController#index","meta.remote_ip":"127.0.0.1","meta.feature_category":"projects","remote_ip":"127.0.0.1","user_id":1,"username":"root","ua":"Mozilla/5.0 (Macintosh; Intel Mac OS X 10.15; rv:99.0) Gecko/20100101 Firefox/99.0","queue_duration_s":0.403126,"request_urgency":"default","target_duration_s":1,"gitaly_calls":8,"gitaly_duration_s":0.109831,"redis_calls":103,"redis_duration_s":0.016210000000000002,"redis_read_bytes":6707,"redis_write_bytes":447353,"redis_cache_calls":97,"redis_cache_duration_s":0.014356,"redis_cache_read_bytes":6458,"redis_cache_write_bytes":446061,"redis_shared_state_calls":3,"redis_shared_state_duration_s":0.0004,"redis_shared_state_write_bytes":190,"redis_sessions_calls":3,"redis_sessions_duration_s":0.001454,"redis_sessions_read_bytes":249,"redis_sessions_write_bytes":1102,"db_count":72,"db_write_count":0,"db_cached_count":19,"db_replica_count":0,"db_primary_count":72,"db_main_count":60,"db_main_replica_count":0,"db_replica_cached_count":0,"db_primary_cached_count":19,"db_main_cached_count":19,"db_main_replica_cached_count":0,"db_replica_wal_count":0,"db_primary_wal_count":0,"db_main_wal_count":0,"db_main_replica_wal_count":0,"db_replica_wal_cached_count":0,"db_primary_wal_cached_count":0,"db_main_wal_cached_count":0,"db_main_replica_wal_cached_count":0,"db_replica_duration_s":0.0,"db_primary_duration_s":0.145,"db_main_duration_s":0.109,"db_main_replica_duration_s":0.0,"external_http_count":1,"external_http_duration_s":0.19882399999187328,"cpu_s":4.398838,"pid":60240,"db_duration_s":0.09991,"view_duration_s":1.38638,"duration_s":4.9204}

On this branch:

{"method":"GET","path":"/","format":"html","controller":"RootController","action":"index","status":200,"time":"2022-04-22T00:03:30.489Z","params":[],"correlation_id":"01G17998TBE7ANQ6K1GTWD7ZVA","meta.user":"root","meta.client_id":"user/1","meta.caller_id":"RootController#index","meta.remote_ip":"127.0.0.1","meta.feature_category":"projects","remote_ip":"127.0.0.1","user_id":1,"username":"root","ua":"Mozilla/5.0 (Macintosh; Intel Mac OS X 10.15; rv:99.0) Gecko/20100101 Firefox/99.0","queue_duration_s":2.659144,"request_urgency":"default","target_duration_s":1,"gitaly_calls":8,"gitaly_duration_s":0.068593,"redis_calls":80,"redis_duration_s":0.008258,"redis_read_bytes":12816,"redis_write_bytes":381335,"redis_cache_calls":77,"redis_cache_duration_s":0.007995,"redis_cache_read_bytes":12571,"redis_cache_write_bytes":380143,"redis_shared_state_calls":2,"redis_shared_state_duration_s":0.000112,"redis_shared_state_write_bytes":104,"redis_sessions_calls":1,"redis_sessions_duration_s":0.000151,"redis_sessions_read_bytes":245,"redis_sessions_write_bytes":1088,"db_count":108,"db_write_count":0,"db_cached_count":0,"db_replica_count":0,"db_primary_count":108,"db_main_count":84,"db_main_replica_count":0,"db_ci_count":24,"db_ci_replica_count":0,"db_replica_cached_count":0,"db_primary_cached_count":0,"db_main_cached_count":0,"db_main_replica_cached_count":0,"db_ci_cached_count":0,"db_ci_replica_cached_count":0,"db_replica_wal_count":0,"db_primary_wal_count":0,"db_main_wal_count":0,"db_main_replica_wal_count":0,"db_ci_wal_count":0,"db_ci_replica_wal_count":0,"db_replica_wal_cached_count":0,"db_primary_wal_cached_count":0,"db_main_wal_cached_count":0,"db_main_replica_wal_cached_count":0,"db_ci_wal_cached_count":0,"db_ci_replica_wal_cached_count":0,"db_replica_duration_s":0.0,"db_primary_duration_s":0.174,"db_main_duration_s":0.13,"db_main_replica_duration_s":0.0,"db_ci_duration_s":0.044,"db_ci_replica_duration_s":0.0,"external_http_count":1,"external_http_duration_s":0.008505999983754009,"cpu_s":4.399919,"pid":60240,"db_duration_s":0.05617,"view_duration_s":0.9641,"duration_s":1.53026}

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Thanks to @igorwwwwwwwwwwwwwwwwwwww for the initial bug report