[ML] Hide inference stats for PyTorch models (elastic#160599)

## Summary

Resolves elastic#157385

Hides inference stats for the PyTorch models. 

- The salient information (`inference_count`, `timestamp`) is a repeat
of what is already displayed in the Deployment Stats section.
- `missing_all_fields_count` is confusing as the PyTorch models take a
single input field rather than multiple fields as DFA models do, hence
omitted.
- The deployment stats have an
[error_count](https://www.elastic.co/guide/en/elasticsearch/reference/current/get-trained-models-stats.html)
field, hence it has been added to the Deployment Stats and
`failure_count` has been removed.
- Displays the stats tab by default for expanded rows if the model has
started deployments

x-pack/packages/ml/trained_models_utils/src/constants/trained_models.ts

@@ -61,12 +61,8 @@ export const ELASTIC_MODEL_DEFINITIONS = {
 
 export const MODEL_STATE = {
   ...DEPLOYMENT_STATE,
-  DOWNLOADING: i18n.translate('xpack.ml.trainedModels.modelsList.downloadingStateLabel', {
-    defaultMessage: 'downloading',
-  }),
-  DOWNLOADED: i18n.translate('xpack.ml.trainedModels.modelsList.downloadedStateLabel', {
-    defaultMessage: 'downloaded',
-  }),
+  DOWNLOADING: 'downloading',
+  DOWNLOADED: 'downloaded',
 } as const;
 
-export type ModelState = typeof MODEL_STATE[keyof typeof MODEL_STATE];
+export type ModelState = typeof MODEL_STATE[keyof typeof MODEL_STATE] | null;

x-pack/plugins/ml/common/types/trained_models.ts

@@ -202,6 +202,7 @@ export interface AllocatedModel {
     throughput_last_minute: number;
     number_of_allocations: number;
     threads_per_allocation: number;
+    error_count?: number;
   };
 }
 

x-pack/plugins/ml/public/application/memory_usage/nodes_overview/allocated_models.tsx

@@ -220,6 +220,16 @@ export const AllocatedModels: FC<AllocatedModelsProps> = ({
         return v.node.number_of_pending_requests;
       },
     },
+    {
+      name: i18n.translate('xpack.ml.trainedModels.nodesList.modelsList.errorCountHeader', {
+        defaultMessage: 'Errors',
+      }),
+      width: '60px',
+      'data-test-subj': 'mlAllocatedModelsTableErrorCount',
+      render: (v: AllocatedModel) => {
+        return v.node.error_count ?? 0;
+      },
+    },
   ].filter((v) => !hideColumns.includes(v.id!));
 
   return (