[Security Solution][Endpoint] Add missing system_indices_superuser role to the Serverless role.yml override file (#167450)

## Summary

- Adds the missing `system_indices_superuser` role to the `role.yml`
file used when starting ES for serverless and using the security
solution override files for resources

x-pack/plugins/security_solution/scripts/endpoint/common/roles_users/serverless/es_serverless_resources/roles.yml

@@ -1,4 +1,17 @@
 ---
+system_indices_superuser:
+  cluster: ['all']
+  indices:
+    - names: ['*']
+      privileges: ['all']
+      allow_restricted_indices: true
+  applications:
+    - application: '*'
+      privileges: ['*']
+      resources: ['*']
+  run_as: ['*']
+
+
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