TriggerEDM: Fix trigger EDM HLTNav entries and test_trigP1_PEB_DS_build (ATR-29945)

• Addresses failures of test_trigP1_PEB_DS_build.py nightly:

  • Test started failing after implementing an EDM checker that runs during configuration whenever user sets an ExtraEDMList.
  • EDM checker uncovered some violations of the new EDM entries in this test, which are now addressed.
  • Test was also failing the "all 'allowTruncation' entries at end of list" check because HLT Navigation containers are added to the end of the EDM list in run time. Adding the HLT Nav containers to start of the list, on the other hand, caused deserialisation issues. A new function getSafeEDMInsertPosition is used to insert new HLT Nav and extra EDM entries at the end but before "allowTruncation" items to minimally impact the order of the original list.

• Fixes a list bug in TriggerConfig.py:

  • Bug corrects some transient HLT Nav container names in the EDM list and/or HLT Nav container remap links and PEB properties. These transient containers aren't written to any output unless flags.Trigger.doOnlineNavigationCompactification is disabled (nominally it is not).
  • Since affected containers aren't nominally marked to be recorded, appears to have had little impact.