[Upgrade Assistant] Removes unnecessary mappings for reindexing (#150878

)

## Summary
Partially addresses #64547

This PR removes unnecessary mappings from the saved objects type
`upgrade-assistant-reindex-operation` that holds information about
reindex processes.
Currently, the reindexing is disabled via a config for Upgrade Assistant
plugin `xpack.upgrade_assistant.featureSet.reindexCorrectiveActions`. ES
also doesn't log any deprecations for indices created since 7.0 and
indices created before 7.0 are incompatible with versions 8.0+. That
means that when reindexing will be enabled in UA, it needs to be
configured for the specific upgrade scenario, for example for 9.0.

### How to test
Even though reindexing is currently disabled, I was able to do some
testing for the changes. Here is how to test reindexing locally:
1. Add `xpack.upgrade_assistant.featureSet.reindexCorrectiveActions:
true` to your `kibana.dev.yml` file
2. Start ES and Kibana with `yarn es snapshot --license=trial` and `yarn
start`
3. Create a test user with the role `system_indices_superuser` (in Stack
Management -> Security -> Users). Log in with that user for further
steps.
4. Create an index via Dev Tools 
```
POST /old_index/_doc
{
  "test": "test"
}
```
5. replace `deprecations` on line 22 in the file
[`/server/lib/es_deprecations_status.ts`](https://github.com/elastic/kibana/blob/main/x-pack/plugins/upgrade_assistant/server/lib/es_deprecations_status.ts#L22)
with
```
  const deprecations = {
    cluster_settings: [],
    node_settings: [],
    ml_settings: [],
    index_settings: {
      old_index: [
        {
          level: 'critical',
          message: 'Index created before 7.0',
          url: 'https: //www.elastic.co/guide/en/elasticsearch/reference/master/breaking-changes-8.0.html',
          details: 'This index was created using version: 6.8.13',
          resolve_during_rolling_upgrade: false,
        },
      ],
    },
  };
```
6. open UA and test the reindexing of `old_index`

### Follow up work
A follow up PR if needed will be opened for saved objects types
`upgrade-assistant-ml-upgrade-operation` and
`upgrade-assistant-telemetry`

src/core/server/integration_tests/saved_objects/migrations/group2/check_registered_types.test.ts

@@ -144,7 +144,7 @@ describe('checking migration metadata changes on all registered SO types', () =>
         "telemetry": "561b329aaed3c15b91aaf2075645be3097247612",
         "ui-metric": "410a8ad28e0f44b161c960ff0ce950c712b17c52",
         "upgrade-assistant-ml-upgrade-operation": "e20ff1efa3c4757f5e7ff5fb897c557b08524c3a",
-        "upgrade-assistant-reindex-operation": "c7442ffe34954c117a74bf138e48e4c25095a6cf",
+        "upgrade-assistant-reindex-operation": "09ac8ed9c9acf7e8ece8eafe47d7019ea1472144",
         "upgrade-assistant-telemetry": "12bcbfc4e4ce64d2ca7c24f9acccd331a2bd2ab6",
         "uptime-dynamic-settings": "9a63ce80904a04be114749e426882dc3ff011137",
         "uptime-synthetics-api-key": "599319bedbfa287e8761e1ba49d536417a33fa13",

x-pack/plugins/upgrade_assistant/server/saved_object_types/reindex_operation_saved_object_type.ts

@@ -14,72 +14,14 @@ export const reindexOperationSavedObjectType: SavedObjectsType = {
   hidden: false,
   namespaceType: 'agnostic',
   mappings: {
+    dynamic: false,
     properties: {
-      reindexTaskId: {
-        type: 'text',
-        fields: {
-          keyword: {
-            type: 'keyword',
-            ignore_above: 256,
-          },
-        },
-      },
       indexName: {
         type: 'keyword',
       },
-      newIndexName: {
-        type: 'text',
-        fields: {
-          keyword: {
-            type: 'keyword',
-            ignore_above: 256,
-          },
-        },
-      },
       status: {
         type: 'integer',
       },
-      locked: {
-        type: 'date',
-      },
-      lastCompletedStep: {
-        type: 'long',
-      },
-      // Note that reindex failures can result in extremely long error messages coming from ES.
-      // We need to map these errors as text and use ignore_above to prevent indexing really large
-      // messages as keyword. See https://github.com/elastic/kibana/issues/71642 for more info.
-      errorMessage: {
-        type: 'text',
-        fields: {
-          keyword: {
-            type: 'keyword',
-            ignore_above: 256,
-          },
-        },
-      },
-      reindexTaskPercComplete: {
-        type: 'float',
-      },
-      runningReindexCount: {
-        type: 'integer',
-      },
-      reindexOptions: {
-        properties: {
-          openAndClose: {
-            type: 'boolean',
-          },
-          queueSettings: {
-            properties: {
-              queuedAt: {
-                type: 'long',
-              },
-              startedAt: {
-                type: 'long',
-              },
-            },
-          },
-        },
-      },
     },
   },
 };