[Fleet] Don't error on missing package_assets value (#91744) (#92003)

## Summary
closes #89111

 * Update TS type to make `package_assets` key in EPM packages saved object optional
 * Update two places in code to deal with optional vs required property

### Checklist

- [ ] [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

#### Manual testing
1. checkout `7.10` branch
   1. **start ES:** `nvm use; yarn kbn bootstrap; yarn es snapshot --version 7.10.3 --license=trial  -E xpack.security.authc.api_key.enabled=true -E path.data=../data`
   1. **start Kibana**: `yarn start --no-base-path`
   1. **run** `curl -X POST -H 'kbn-xsrf: 1234' --user elastic:changeme localhost:5601/api/fleet/setup`
   2. **observe** `{"is_initialized: true}`
1. checkout `7.11` branch
   1. **start ES:** `nvm use; yarn kbn bootstrap; yarn es snapshot --version 7.11.1 --license=trial  -E xpack.security.authc.api_key.enabled=true -E path.data=../data`
   1. **start Kibana**: `yarn start --no-base-path`
   1. **run** `curl -X POST -H 'kbn-xsrf: 1234' --user elastic:changeme localhost:5601/api/fleet/setup`
   1. **observe** `{"is_initialized: true}`
1. checkout `master` branch
   1. **start ES:** `nvm use; yarn kbn bootstrap; yarn es snapshot --version 8.0.0 --license=trial  -E xpack.security.authc.api_key.enabled=true -E path.data=../data`
   1. **start Kibana**: `yarn start --no-base-path`
   1. **run** `curl -X POST -H 'kbn-xsrf: 1234' --user elastic:changeme localhost:5601/api/fleet/setup`
   1. **observe error** {"statusCode":500,"error":"Internal Server Error","message":"Cannot read property 'map' of undefined"}
1. checkout this PR `8911-fleet-startup-error`
   1. **start ES:** `nvm use; yarn kbn bootstrap; yarn es snapshot --version 8.0.0 --license=trial  -E xpack.security.authc.api_key.enabled=true -E path.data=../data`
   1. **start Kibana**: `yarn start --no-base-path`
   1. **run** `curl -X POST -H 'kbn-xsrf: 1234' --user elastic:changeme localhost:5601/api/fleet/setup`
   1. **observe success** `{"is_initialized: true}`

**_Notes_**
 * _you might need to do a `yarn kbn clean` when starting kibana if it fails. There have been some big changes in the tooling recently_

Co-authored-by: John Schulz <john.schulz@elastic.co>

x-pack/plugins/fleet/common/types/models/epm.ts

@@ -273,7 +273,7 @@ export type PackageInfo =
 export interface Installation extends SavedObjectAttributes {
   installed_kibana: KibanaAssetReference[];
   installed_es: EsAssetReference[];
-  package_assets: PackageAssetReference[];
+  package_assets?: PackageAssetReference[];
   es_index_patterns: Record<string, string>;
   name: string;
   version: string;

x-pack/plugins/fleet/server/services/epm/archive/storage.ts

@@ -83,9 +83,10 @@ export async function archiveEntryToESDocument(opts: {
 
 export async function removeArchiveEntries(opts: {
   savedObjectsClient: SavedObjectsClientContract;
-  refs: PackageAssetReference[];
+  refs?: PackageAssetReference[];
 }) {
   const { savedObjectsClient, refs } = opts;
+  if (!refs) return;
   const results = await Promise.all(
     refs.map((ref) => savedObjectsClient.delete(ASSETS_SAVED_OBJECT_TYPE, ref.id))
   );

x-pack/plugins/fleet/server/services/epm/packages/get.ts

@@ -16,6 +16,7 @@ import {
 import { PACKAGES_SAVED_OBJECT_TYPE } from '../../../constants';
 import { ArchivePackage, RegistryPackage, EpmPackageAdditions } from '../../../../common/types';
 import { Installation, PackageInfo, KibanaAssetType } from '../../../types';
+import { IngestManagerError } from '../../../errors';
 import * as Registry from '../registry';
 import { createInstallableFrom, isRequiredPackage } from './index';
 import { getEsPackage } from '../archive/storage';
@@ -185,7 +186,8 @@ export async function getPackageFromSource(options: {
       name: pkgName,
       version: pkgVersion,
     });
-    if (!res) {
+
+    if (!res && installedPkg.package_assets) {
       res = await getEsPackage(
         pkgName,
         pkgVersion,
@@ -207,7 +209,9 @@ export async function getPackageFromSource(options: {
     // else package is not installed or installed and missing from cache and storage and installed from registry
     res = await Registry.getRegistryPackage(pkgName, pkgVersion);
   }
-  if (!res) throw new Error(`package info for ${pkgName}-${pkgVersion} does not exist`);
+  if (!res) {
+    throw new IngestManagerError(`package info for ${pkgName}-${pkgVersion} does not exist`);
+  }
   return {
     paths: res.paths,
     packageInfo: res.packageInfo,