[ML] Data frame analytics results grid should use index pattern field format if one exists

[Winterflower]

Kibana version:
STACK_BUILD=2227
STACK_VERSION=7.7.0

Elasticsearch version:
STACK_BUILD=2227
STACK_VERSION=7.7.0

Server OS version:
N/A
Browser version:
Chrome
Browser OS version:
Mac OS X

Steps to reproduce:

1. Restore the seeds dataset and run the multiclass ML job linked in the Configuration section below
2. After job is complete (should be fast since this dataset only has 210 datapoints), click on "View" and look at the data in the table.
3. You will see that most of the entries in the data table are rounded to three decimal points, while some appear to display a lot more decimal points. This increased precision does not match what you would see if you looked at the data in Discover.

There are two issues here:

1. Inconsistent rounding among data points in the DF Analytics results table (see screenshot above)
2. Introducing more floating points than the source data

Source Data in the Discover tab

Same data point in the ML DF Analytics Results UI

ML Job Configuration

PUT _ml/data_frame/analytics/seeds
{
  "source": {
    "index": "seeds"
  },
  "dest": {
    "index":"seeds_results"
    
  },
  "model_memory_limit": "2gb",
  "analysis": 
    {
      "classification": {
        "num_top_classes" : 2,
        "dependent_variable": "seed_class",
        "training_percent": 80
      }
    }
}

[elasticmachine]

Pinging @elastic/ml-ui (:ml)

[alvarezmelissa87]

Hey @Winterflower 😄

This isn't a UI issue as far as I can tell. The UI doesn't do any rounding here in the case of number type when displaying it in the data table. Numbers are displayed as they are.

These are the values stored on the job result index that's being queried.

The original seeds index viewed in discover for this particular record:

The same record stored in the classification job's result index:

Must be some change happening on the back-end.

[peteharverson]

If an index pattern exists for the destination index, the values in the results grid should be formatted using the field format from the index pattern. For the case above, this would result in the data grid formatting values to 3 d.p. in common with Discover. If no index pattern exists for the destination index, we should probably check for an index pattern for the source index.