Explicitly reference the CONTENT_API_ENDPOINT
Explicitly reference the CONTENT_API_ENDPOINT

Probably because of variable load-order, the test failed on my machine.
This change should make it deterministic.

bitzesty/gds-api-adapters,theodi/gds-api-adapters,bitzesty/gds-api-adapters,theodi/gds-api-adapters,alphagov/gds-api-adapters