GSF track thinning also includes forward electrons for run 4

For ITk geometry, forward electrons can now be associated to GSF track particles. But up to now, thinning was not looking at these electrons, and the associated GSF track particles were removed by the egammaTrackThinner algorithm. This MR fixes this.

added Egamma Reconstruction Upgrade labels

This merge request affects 1 package:

• Reconstruction/egamma/egammaAlgs

This merge request affects 3 files:

• Reconstruction/egamma/egammaAlgs/python/egammaTrackThinnerConfig.py
• Reconstruction/egamma/egammaAlgs/src/egammaTrackThinner.cxx
• Reconstruction/egamma/egammaAlgs/src/egammaTrackThinner.h

Adding @goetz as watcher

added main review-pending-level-1 labels

CI Result SUCCESS (hash 78dcd45b)

	Athena
externals
cmake
make
tests

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Athena: number of compilation errors 0, warnings 0
For experts only: Jenkins output [CI-MERGE-REQUEST-EL9 4107]

removed review-pending-level-1 label

added review-approved label

merged

mentioned in commit 3676260a