Update the unit tests in models-provider so that we can check that the
TOSCA artifact that is read from the database is the same as the TOSCA
artifact that is stored.
This review does some groundwork for that check.
Issue-ID: POLICY-2315
Change-Id: Iabc7b247736b862713585a493752bc254cfe1c3d
Signed-off-by: liamfallon <liam.fallon@est.tech>