IInDetConditionsSvc: use DeclareInterfaceID for interface
In !74923 (merged) the TRT_ConditionsSummarySvc
was changed to inherit via Gaudi's extends
formalism. However, one of the interfaces didn't use the required DeclareInterfaceID
which then broke the test_TRTCalibration.sh
ART test.
Thanks to @serodrig for reporting.