Update _helpers.tpl

[thunderthome]

Make sure that prometheus internal enabled really works (that i can disable it).

[toscott]

Hi @thunderthome. Can you help me understand the use case here?

Opencost requires a prometheus endpoint. The options are basically an external one or an internal one. If its internal, the network policy gets added (which doesn't hurt to add if its an external prometheus, so its just defaulted on.

[thunderthome]

@toscott the reason I want to add this is because now if I turn on Thanos my values aren't used because it has the fallback in the prometheus setup. I wanted to use it internally at first, but one of my colleagues pointed to me that we use Thanos. Now if I want to enable Thanos and disable internal Prometheus it won't let me do that because of this fallback.