Add extra eta FlowElement validation plot

Hi (cc @mhodgkin )

This MR adds an additional plot for the FlowElement validation routine, covering the distribution of Eta given E>0.

Thanks

Matt A.

PS: this also includes the changes seen in MR: !39082 (merged), so will hold WIP until that is merged.

added 1208 commits

• 23c98267...7bb6c91e - 1206 commits from branch atlas:master
• 0b66d0ec - fix merge conflicts
• a13851ff - fix bad merge

Compare with previous version

unmarked as a Work In Progress

This merge request affects 2 packages:

• Reconstruction/PFlow/PFlowUtils
• Reconstruction/PFlow/PFlowValidation/PFOHistUtils

Affected files list will not be printed in this case

Adding @goetz ,@mhodgkin as watchers

added JetEtmiss Reconstruction master review-pending-level-1 labels

CI Result SUCCESS (hash a13851ff)

	Athena	AthSimulation	AthGeneration	AnalysisBase	AthAnalysis
externals
cmake
make
required tests
optional tests

Full details available on this CI monitor view
Athena: number of compilation errors 0, warnings 0
AthSimulation: number of compilation errors 0, warnings 0
AthGeneration: number of compilation errors 0, warnings 0
AnalysisBase: number of compilation errors 0, warnings 0
AthAnalysis: number of compilation errors 0, warnings 0
For experts only: Jenkins output [CI-MERGE-REQUEST-CC7 25990]

• Minor code changes - from a sweep (not all changes appear, but assume that is ok)
• Added one new plot
• all tests passing

Approving (L1)

removed review-pending-level-1 label

added review-pending-level-2 label

Looks fine to me as well, approving.

Pavol [as L2 MR shifter]

added review-approved label and removed review-pending-level-2 label

merged

mentioned in commit 9c3e0b43

added sweep:ignore label