Fix to VSI track association

This MR will fix an issue in the VrtSecInclusive algorithm. The fix will change the track attachment step, so that each track is attached to the vertex before the algorithm attempts to attach another track. Without this fix, some secondary vertices only have 1 attached track, when they should have more. The issue is described in detail here (https://gitlab.cern.ch/atlas-phys-susy-wg/RPVLL/DisplacedVertices/athena/-/issues/4), which includes plots showing the impact of this fix on secondary vertices in some MC and data events.

Tagging @cohm , @leejr , @spagan , @hoide

added alsoTargeting:21.0 label

build area is cleaned as the previous build was for the MR labeled as full-build

This merge request affects 1 package:

• Reconstruction/VKalVrt/VrtSecInclusive

Adding @goetz as watcher

added 21.2 Reconstruction review-pending-level-1 labels

Two CI jobs are triggered by 21.2 MR events: for AthDerivation with gcc62 compiler and with gcc8 for AnalysisBase and AthAnalysis projects.

• Developers and shifters need to wait for both results, sometimes for additional hour or two.

CI Result SUCCESS (hash d065294e)

	AnalysisBase	AthAnalysis
externals
cmake
make
required tests
optional tests

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AnalysisBase: number of compilation errors 0, warnings 0
AthAnalysis: number of compilation errors 0, warnings 6
For experts only: Jenkins output [CI-MERGE-REQUEST-CC7 20595]

CI Result SUCCESS (hash d065294e)

	AthDerivation
externals
cmake
make
required tests
optional tests

Full details available on this CI monitor view
AthDerivation: number of compilation errors 0, warnings 17
For experts only: Jenkins output [CI-MERGE-REQUEST-GCC62-CC7 27]

Changes are straightforward, tests pass, except for unrelated build warnings. L1 approving.

added review-approved label and removed review-pending-level-1 label

Hi, @krumnack would you please take a look and merge this?

Best regards, Rui, AR shifter

merged

mentioned in commit 66aabce6

@egramsta, @guirriec, @boeriu: Just tagging you as an FYI, as this may affect derivations.

added sweep:done label

picked the changes into the branch cherry-pick-66aabce6d2a-21.0 with commit 66e5ff23

mentioned in commit 66e5ff23

Sweep summary
successful:

• 21.0

(see https://aiatlas154.cern.ch/jenkins/job/auto_git_sweeps/1283/console for details)

mentioned in merge request !36533 (merged)

Thanks @emily! The sweep to 21.0 was successful

mentioned in commit 904ea003