L1: fix internal reco time calculation wihen using sub-slices

Fix the internal reco timer that was broken because of the sub-slices. Redmine issue: https://redmine.cbm.gsi.de/issues/2142

The MR comes on top of !423 (merged)

added BugFix label

mentioned in merge request !428 (merged)

Dear @se.gorbunov, @v.akishina,

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.

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added 9 commits

• 5b876fc9...4f121731 - 8 commits from branch computing:master
• 59bdba85 - L1: fix internal reco time calculation wihen using sub-slices

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enabled an automatic merge when the pipeline for 59bdba85 succeeds

merged