Remove forced stub + response check in producer tests

[kayvonghaffari]

There are instances where the input of a request doesn't determine all of the output (for example: token responses in create methods).

The one writing the producer tests will need to explicitly follow this pattern in their tests for cases like this.

it { expect(stub_response).to include(token: "ATstubToken") }
it { is_expected.to include(stub_response.merge(token: /\AAT\w+\z/)) }