This is a temporary solution for now that uses DrawableHitObject.SampleNamespace for the override. We will not want to do this going forward, and instead have the rulesets add their custom resource stores to the games', but that requires deciding where/when to apply/remove such resource stores, and is probably left to skinning.
Not sure if we will keep this going forward (there will likely be an opaque tab control on the notifications overlay similar to options) but let's go with this for now.