[BUG] Omnivore "Get Article" cannot list users

**Describe the bug**
In the Omnivore action "Get Article", a prop supposed to list users seems to always return "unexpected server error".

**To Reproduce**
1. Create an action step using the "Get Article" component;
2. Attempt to load the list of users in the first prop.

**Expected behavior**
The list of users should be loaded.

**Screenshots**

**Additional context**
I've already checked the GraphQL query for listing users, and it seems to [match the schema correctly](https://github.com/omnivore-app/omnivore/blob/40327a50013c8764ba86085d70cb13f9263be931/packages/api/src/schema.ts#L115), so I've sent a message to Omnivore support regarding this.

This issue is being created so that #9898 can be released without losing sight of this bug, since it is unrelated to that issue and happens in the currently live component.