[Fleet] Fix invalid permission entry if the elastic agent package is …

…not installed (elastic#125447) (elastic#125529)

(cherry picked from commit d383bda)

Co-authored-by: Nicolas Chaulet <[email protected]>

x-pack/plugins/fleet/server/services/agent_policies/monitoring_permissions.test.ts

@@ -43,6 +43,15 @@ describe('getMonitoringPermissions', () => {
       );
       expect(permissions).toMatchSnapshot();
     });
+
+    it('should an empty valid permission entry if neither metrics and logs are enabled', async () => {
+      const permissions = await getMonitoringPermissions(
+        savedObjectsClientMock.create(),
+        { logs: false, metrics: false },
+        'testnamespace123'
+      );
+      expect(permissions).toEqual({ _elastic_agent_monitoring: { indices: [] } });
+    });
   });
 
   describe('With elastic agent package installed', () => {

x-pack/plugins/fleet/server/services/agent_policies/monitoring_permissions.ts

@@ -30,6 +30,14 @@ function buildDefault(enabled: { logs: boolean; metrics: boolean }, namespace: s
     );
   }
 
+  if (names.length === 0) {
+    return {
+      _elastic_agent_monitoring: {
+        indices: [],
+      },
+    };
+  }
+
   return {
     _elastic_agent_monitoring: {
       indices: [