[RTA/DPA BW Tests] Attempting to create comparison pages for 'reference builds'

I noticed in https://jenkins-lhcb-nightlies.web.cern.ch/job/nightly-builds/job/tests/5704525/consoleFull that in lhcb-2024-patches.127, i.e.e not a -mr. build, the job still attempts to access comparisons, several times until it finally gives up.

2024-08-30 11:01:03,714 - handlers.BandwidthTestHandler - ERROR - Error getting the data from comparison build/preparing to build comparison page.
...
couchdb.http.ResourceNotFound: Can't find test Moore_hlt2_and_spruce_bandwidth_SMOG2 for slot lhcb-2024-patches-mr.1373
... # Several lines of errors
couchdb.http.ResourceNotFound: Can't find test Moore_hlt2_and_spruce_bandwidth_SMOG2 for slot lhcb-2024-patches-mr.1374
... # and so on

Doesn't look like it harms the job but is a situation we should avoid.