Campaigns endpoint returns random nodes if id matches

[weerd]

BUG

Current Behavior

• A request to the /campaigns endpoint with a seemingly valid id such as:

https://staging.dosomething.org/api/v1/campaigns/504

Will return a response, however the above is a node id for a fact node and not a campaign.

Desired Behavior

• The campaigns endpoint should return an appropriate not found API error response if it id is not for an actual campaign node.

Steps to Replicate

• Hit the above endpoint. You get a response with lots of null values, when you shouldn't get a response at all.

Why This Matters

It's affecting test data on Gladiator at the moment, because we think we're getting valid results with autogenerated campaign ids, which should not be happening.

Related Issue DoSomethingArchive/gladiator#180