Log SQL counts from save pipeline step

What does this MR do and why?

Related to #346246 (closed)

Screenshots or screen recordings

Adds the following entries to the pipeline logger data:

{
  "pipeline_save_duration_s": {
    "count": 1,
    "min": 6.0154480000492185,
    "max": 6.0154480000492185,
    "avg": 6.0154480000492185
  },
  "pipeline_save_db_count": {
    "count": 1,
    "min": 2520,
    "max": 2520,
    "avg": 2520
  },
  "pipeline_save_db_write_count": {
    "count": 1,
    "min": 1865,
    "max": 1865,
    "avg": 1865
  },
  "pipeline_save_db_primary_count": {
    "count": 1,
    "min": 2520,
    "max": 2520,
    "avg": 2520
  },
  "pipeline_save_db_primary_duration_s": {
    "count": 1,
    "min": 11.396,
    "max": 11.396,
    "avg": 11.396
  }
}

Here are all of the keys that it could log

  "pipeline_save_duration_s": {
    "count": 1,
    "min": 5.195619000005536,
    "max": 5.195619000005536,
    "avg": 5.195619000005536
  },
  "pipeline_save_db_count": {
    "count": 1,
    "min": 1008,
    "max": 1008,
    "avg": 1008
  },
  "pipeline_save_db_write_count": {
    "count": 1,
    "min": 746,
    "max": 746,
    "avg": 746
  },
  "pipeline_save_db_cached_count": {
    "count": 1,
    "min": 0,
    "max": 0,
    "avg": 0
  },
  "pipeline_save_db_replica_count": {
    "count": 1,
    "min": 0,
    "max": 0,
    "avg": 0
  },
  "pipeline_save_db_primary_count": {
    "count": 1,
    "min": 1008,
    "max": 1008,
    "avg": 1008
  },
  "pipeline_save_db_replica_cached_count": {
    "count": 1,
    "min": 0,
    "max": 0,
    "avg": 0
  },
  "pipeline_save_db_primary_cached_count": {
    "count": 1,
    "min": 0,
    "max": 0,
    "avg": 0
  },
  "pipeline_save_db_replica_wal_count": {
    "count": 1,
    "min": 0,
    "max": 0,
    "avg": 0
  },
  "pipeline_save_db_primary_wal_count": {
    "count": 1,
    "min": 0,
    "max": 0,
    "avg": 0
  },
  "pipeline_save_db_replica_wal_cached_count": {
    "count": 1,
    "min": 0,
    "max": 0,
    "avg": 0
  },
  "pipeline_save_db_primary_wal_cached_count": {
    "count": 1,
    "min": 0,
    "max": 0,
    "avg": 0
  },
  "pipeline_save_db_replica_duration_s": {
    "count": 1,
    "min": 0,
    "max": 0,
    "avg": 0
  },
  "pipeline_save_db_primary_duration_s": {
    "count": 1,
    "min": 4.672,
    "max": 4.672,
    "avg": 4.672
  },

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