How to set X-pack settings for elastic.co?

I'm running an Elastic Cloud based instance of Kibana and I want to set the following:

xpack.reporting.csv.maxSizeBytes: 104857600

Which is 10x the default.

Where do I set this? If I try setting it in the elasticsearch.yml User Settings section for my cluster, it gives me an error message saying "Illegal user settings" when I click the Update button.

Hi @nzjess

For Elastic Cloud inquiries, see Now Live! New Elastic Cloud Standard Support1.
This channel is dedicated for Elastic Cloud Enterprise which is another product.

Thanks,
Uri