fix(distops): D018_01 loop detection on a redirect registration, where 508 is the answer

Loop detection on a redirect registration.

Spec: TS 104-176 clause 6.3.5: "In the case of an exclusive or redirect registration, where all of the data is held outside of the Context Broker and held in a single registered source", the answer is "508 Loop Detected - if the single registered source and tenant is registered to redirect back on to the Context Broker". For an inclusive registration the data is also held locally, so 508 does not follow.

Change: D018_01 registers its loop as redirect (was inclusive). Redirect, because the fixture carries entities only, and an exclusive registration needs attribute names.

Effect (against coraine): D018_01 fails on develop and passes with this MR. The rest of LoopDetection passes on both.

Checks run: robocop format --check (0 files), scripts/find_unused_test_data.py (nothing new), statisticsDocumentationData.py (0 of 625 failed), doc unit tests OK.

Fix MR 14 of the plan: https://famzang.com/ttf/ngsi-ld-suite-plan.html