accounting: use MovementHistoryListBrain.mirror_section_title directly

This compatibibility script was guessing the side, but this is exposed
in brain
9 jobs for feat/brain_is_source in 0 seconds
Status Job ID Name Coverage
  External
passed ERP5.CodingStyleTest-Master

01:27:30

passed ERP5.PerformanceTest-Master

00:26:57

failed ERP5.UnitTest-Master

01:45:11

failed ERP5.UnitTest-Zope2

04:21:13

passed SlapOS.Eggs.UnitTest-Master.Python2

00:13:13

passed SlapOS.Eggs.UnitTest-Master.Python3

00:14:00

passed Wendelin.UnitTest-Master

00:29:52

passed SlapOS.Eggs.UnitTest-Master.Python2

00:12:53

passed SlapOS.Eggs.UnitTest-Master.Python3

00:21:08