Remove SavedObjects missing index error handling and associated error UI.

[rudolf]

From what I can tell, before we had Saved Object migrations, it was possible for the SavedObjectsClient/repository to get a NotFound error when creating an Saved Object because the .kibana index doesn't yet exist and ES's auto create index setting was disabled. Since the migration framework handles creating the index, this would no longer be a common occurrence and would only happen in exceptional circumstances like if someone manually deleted their indexes. Simply throwing the raw NotFound error from ES is probably sufficient.

kibana/src/core/server/saved_objects/service/lib/repository.ts

Lines 267 to 270 in bbf703a

	if (SavedObjectsErrorHelpers.isNotFoundError(error)) {
	// See "503s from missing index" above
	throw SavedObjectsErrorHelpers.createEsAutoCreateIndexError();
	}

kibana/src/core/public/saved_objects/saved_objects_client.ts

Lines 32 to 37 in 9d3d3cd

	// TODO: Migrate to an error modal powered by the NP?
	import {
	isAutoCreateIndexError,
	showAutoCreateIndexErrorPage,
	// eslint-disable-next-line @kbn/eslint/no-restricted-paths
	} from '../../../legacy/ui/public/error_auto_create_index/error_auto_create_index';

kibana/src/core/server/saved_objects/types.ts

Lines 218 to 225 in 054ec70

	* ### 503s from missing index
	*
	* Unlike all other methods, create requests are supposed to succeed even when
	* the Kibana index does not exist because it will be automatically created by
	* elasticsearch. When that is not the case it is because Elasticsearch's
	* `action.auto_create_index` setting prevents it from being created automatically
	* so we throw a special 503 with the intention of informing the user that their
	* Elasticsearch settings need to be updated.

kibana/src/core/server/saved_objects/service/lib/errors.ts

Lines 167 to 177 in 260d907

	public static createEsAutoCreateIndexError() {
	const error = Boom.serverUnavailable('Automatic index creation failed');
	error.output.payload.attributes = error.output.payload.attributes || {};
	error.output.payload.attributes.code = 'ES_AUTO_CREATE_INDEX_ERROR';
	return decorate(error, CODE_ES_AUTO_CREATE_INDEX_ERROR, 503);
	}
	public static isEsAutoCreateIndexError(error: Error | DecoratedError) {
	return isSavedObjectsClientError(error) && error[code] === CODE_ES_AUTO_CREATE_INDEX_ERROR;
	}

https://github.com/elastic/kibana/blob/ea9721ad13d1496ebb96dfc6647699c21967fb91/src/legacy/ui/public/error_auto_create_index/error_auto_create_index.ts

[elasticmachine]

Pinging @elastic/kibana-platform (Team:Platform)

[joshdover]

Duplicate of #63894