ATR-26899: removing import of ConfigFlags in TriggerEDM.py

Following up on ATR-26899, I removed the import of ConfigFlags and consequently also the related if statement.

This only addresses the first part of the work, as @fwinkl had commented on !36865 (merged), some more work might be needed to do the manipulation of the TriggerEDMRun3 list within the EDM package.