fix memory leak in timebased simulations of TRD2D (A.Nan)

Fixes an error in TRD2D digi management for timebased simulations. The problem was reported here https://redmine.cbm.gsi.de/issues/2598

and also reported by NH in private communication.

@n.herrmann FYI

Dear @a.bercuci, @p.kaehler,

you have been identified as code owner of at least one file which was changed with this merge request.

Please check the changes and approve them or request changes.

added CodeOwners label

assigned to @f.uhlig

requested review from @v.friese

Can you briefly explain why this is needed to prevent a memory leak?

added 23 commits

• d97aefa6...b26587d9 - 21 commits from branch computing:master
• 1756635a - fix memory leak in timebased simulations of TRD2D (A.Nan)
• 75e5e7a2 - replace hard-codded value by significant parameter

Compare with previous version

resolved all threads

added 10 commits

• 75e5e7a2...18049ca4 - 8 commits from branch computing:master
• 48d585cb - fix memory leak in timebased simulations of TRD2D (A.Nan)
• cf005e1d - replace hard-codded value by significant parameter

Compare with previous version

enabled an automatic merge when the pipeline for cf005e1d succeeds

@v.friese,

I merge the request. @a.bercuci did the requested fix.

merged