[Security Solution] Set the Get File feature flag to true by default (#149612)

## Summary

Sets the Get File feature flag to true by default in preparation for the
release of the feature.

### 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

---------

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

x-pack/test/api_integration/apis/security/privileges_basic.ts

@@ -120,6 +120,7 @@ export default function ({ getService }: FtrProviderContext) {
               'read',
               'trusted_applications_all',
               'trusted_applications_read',
+              'file_operations_all',
             ],
             uptime: ['all', 'read', 'minimal_all', 'minimal_read'],
             securitySolutionCases: ['all', 'read', 'minimal_all', 'minimal_read', 'cases_delete'],