removed ESO migration from alerting (#73420) (#73452)

This PR removes the use of ESO migration from alerting as we do not actually need this until the RBAC work lands, which should be 7.10.
This allows us to concentrate the challenges of introducing RBAC into one single release which hopefully will help us better mitigate potential regressions.

Author: gmmorris

x-pack/plugins/alerts/server/saved_objects/index.ts

@@ -6,7 +6,6 @@
 
 import { SavedObjectsServiceSetup } from 'kibana/server';
 import mappings from './mappings.json';
-import { getMigrations } from './migrations';
 import { EncryptedSavedObjectsPluginSetup } from '../../../encrypted_saved_objects/server';
 
 export function setupSavedObjects(
@@ -17,7 +16,6 @@ export function setupSavedObjects(
     name: 'alert',
     hidden: true,
     namespaceType: 'single',
-    migrations: getMigrations(encryptedSavedObjects),
     mappings: mappings.alert,
   });
 

x-pack/plugins/alerts/server/saved_objects/migrations.test.ts

@@ -27,8 +27,5 @@ export default function alertingTests({ loadTestFile }: FtrProviderContext) {
     loadTestFile(require.resolve('./alerts_space1'));
     loadTestFile(require.resolve('./alerts_default_space'));
     loadTestFile(require.resolve('./builtin_alert_types'));
-
-    // note that this test will destroy existing spaces
-    loadTestFile(require.resolve('./migrations'));
   });
 }