Add process.Ext.services field to telemetry allowlist (elastic#168147)

## Summary

Adding `process.Ext.services` to the endpoint telemetry allowlist. The
Endpoint Protections team would like to have visibility of this field in
order to write more accurate exceptionlist entries.

### Checklist

- [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

### For maintainers

- [ ] This was checked for breaking API changes and was [labeled
appropriately](https://www.elastic.co/guide/en/kibana/master/contributing.html#kibana-release-notes-process)

x-pack/plugins/security_solution/server/lib/telemetry/filterlists/endpoint_alerts.ts

@@ -29,6 +29,7 @@ const baseAllowlistFields: AllowlistFields = {
     malware_signature: true,
     memory_region: true,
     protection: true,
+    services: true,
     session_info: true,
     real: {
       entity_id: true,

x-pack/plugins/security_solution/server/lib/telemetry/sender.test.ts

@@ -187,6 +187,7 @@ describe('TelemetryEventsSender', () => {
             env_vars: [{ name: 'foo', value: 'bar' }],
             Ext: {
               protection: 'PsProtectedSignerAntimalware-Light',
+              services: ['SepScanService'],
               relative_file_creation_time: 48628704.4029488,
               relative_file_name_modify_time: 48628704.4029488,
               device: {
@@ -384,6 +385,7 @@ describe('TelemetryEventsSender', () => {
             env_vars: [{ name: 'foo', value: 'bar' }],
             Ext: {
               protection: 'PsProtectedSignerAntimalware-Light',
+              services: ['SepScanService'],
               relative_file_creation_time: 48628704.4029488,
               relative_file_name_modify_time: 48628704.4029488,
               device: {