[Security Solution] Add missed policy migration export (#146481)

## Summary

Adds a missing export to the policy migration for 8.6.0

PR with the migration for reference:
https://github.com/elastic/kibana/pull/146050

- [x] [Unit or functional
tests](https://www.elastic.co/guide/en/kibana/master/development-tests.html)
were updated or added to match the most common scenarios

Co-authored-by: Kibana Machine <42973632+kibanamachine@users.noreply.github.com>

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

@@ -104,7 +104,7 @@ describe('checking migration metadata changes on all registered SO types', () =>
         "ingest-agent-policies": "9170cdad95d887c036b87adf0ff38a3f12800c05",
         "ingest-download-sources": "1e69dabd6db5e320fe08c5bda8f35f29bafc6b54",
         "ingest-outputs": "4888b16d55a452bf5fff2bb407e0361567eae63a",
-        "ingest-package-policies": "e8707a8c7821ea085e67c2d213e24efa56307393",
+        "ingest-package-policies": "d93048bf153f9043946e8965065a88014f7ccb41",
         "ingest_manager_settings": "6f36714825cc15ea8d7cda06fde7851611a532b4",
         "inventory-view": "bc2bd1e7ec7c186159447ab228d269f22bd39056",
         "kql-telemetry": "29544cd7d3b767c5399878efae6bd724d24c03fd",

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

@@ -48,7 +48,11 @@ import {
   migratePackagePolicyToV840,
 } from './migrations/to_v8_4_0';
 import { migratePackagePolicyToV850, migrateAgentPolicyToV850 } from './migrations/to_v8_5_0';
-import { migrateSettingsToV860, migrateInstallationToV860 } from './migrations/to_v8_6_0';
+import {
+  migrateSettingsToV860,
+  migrateInstallationToV860,
+  migratePackagePolicyToV860,
+} from './migrations/to_v8_6_0';
 
 /*
  * Saved object types and mappings
@@ -230,6 +234,7 @@ const getSavedObjectTypes = (
       '8.3.0': migratePackagePolicyToV830,
       '8.4.0': migratePackagePolicyToV840,
       '8.5.0': migratePackagePolicyToV850,
+      '8.6.0': migratePackagePolicyToV860,
     },
   },
   [PACKAGES_SAVED_OBJECT_TYPE]: {

x-pack/plugins/fleet/server/saved_objects/migrations/to_v8_6_0.ts

@@ -36,7 +36,7 @@ export const migrateInstallationToV860: SavedObjectMigrationFn<Installation, Ins
   return installationDoc;
 };
 
-export const migratePackagePolicyToV840: SavedObjectMigrationFn<PackagePolicy, PackagePolicy> = (
+export const migratePackagePolicyToV860: SavedObjectMigrationFn<PackagePolicy, PackagePolicy> = (
   packagePolicyDoc,
   migrationContext
 ) => {