refactor: Portal fusing and remove shared-from-this

[paulgessinger]

The shared-from-this functionality in Portal is only needed because Portal::fuse uses it to reset the other fuse partner to itself. This PR changes Portal::fuse into a static symmetric function which returns a new merged portal.

The input portals are invalidated.

It then removes the shared-from-this functionality from portal, as it is no longer needed.

[codecov]

Codecov Report

Attention: 31 lines in your changes are missing coverage. Please review.

Comparison is base (cf84e21) 49.51% compared to head (b03e2ac) 49.52%.

Files	Patch %	Lines
Core/src/Detector/Portal.cpp	68.75%	1 Missing and 14 partials ⚠️
.../src/Detector/detail/CylindricalDetectorHelper.cpp	0.00%	0 Missing and 15 partials ⚠️
Core/src/Detector/PortalGenerators.cpp	0.00%	0 Missing and 1 partial ⚠️

Additional details and impacted files

@@           Coverage Diff           @@
##             main    #2746   +/-   ##
=======================================
  Coverage   49.51%   49.52%           
=======================================
  Files         475      474    -1     
  Lines       26965    26978   +13     
  Branches    12447    12453    +6     
=======================================
+ Hits        13352    13361    +9     
- Misses       4764     4767    +3     
- Partials     8849     8850    +1     

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[github-actions]

📊: Physics performance monitoring for b03e2ac

Full contents

physmon summary

• ✅ CKF truth_smeared
• ✅ IVF truth_smeared
• ✅ AMVF truth_smeared
• ✅ Track Summary CKF truth_smeared
• ✅ Seeding truth_estimated
• ✅ CKF truth_estimated
• ✅ IVF truth_estimated
• ✅ AMVF truth_estimated
• ✅ Track Summary CKF truth_estimated
• ✅ Seeding seeded
• ✅ CKF seeded
• ✅ IVF seeded
• ✅ AMVF seeded
• ✅ AMVF (+grid seeder) seeded
• ✅ Track Summary CKF seeded
• ✅ Seeding orthogonal
• ✅ CKF orthogonal
• ✅ IVF orthogonal
• ✅ AMVF orthogonal
• ✅ Track Summary CKF orthogonal
• ✅ Ambisolver seeded
• ✅ Ambisolver orthogonal
• ✅ Seeding ttbar
• ✅ CKF ttbar
• ✅ Ambisolver
• ✅ Track Summary CKF ttbar
• ✅ AMVF ttbar
• ✅ AMVF (+grid seeder) ttbar
• ✅ Truth tracking (GSF)
• ✅ Truth tracking
• ✅ Particles fatras
• ✅ Particles geant4

[acts-project-service]

✅ Athena integration test results [c676ac1]

✅ All tests successful

status	job
🟢	run_unit_tests
🟢	run_ci_tests: ../athena/AtlasTest/CITest/test/ActsBenchmarkWithSpot.sh 8 100
🟢	run_ci_tests: ../athena/AtlasTest/CITest/test/ActsWorkflow.sh
🟢	run_ci_tests: ../athena/AtlasTest/CITest/test/ActsValidateAmbiguityResolution.sh
🟢	run_ci_tests: ../athena/AtlasTest/CITest/test/ActsValidateResolvedTracks.sh
🟢	run_ci_tests: ../athena/AtlasTest/CITest/test/ActsValidateTracks.sh
🟢	run_ci_tests: ../athena/AtlasTest/CITest/test/ActsValidateActsCoreSpacePoints.sh
🟢	run_ci_tests: ../athena/AtlasTest/CITest/test/ActsValidateActsSpacePoints.sh
🟢	run_ci_tests: ../athena/AtlasTest/CITest/test/ActsValidateSeeds.sh
🟢	run_ci_tests: ../athena/AtlasTest/CITest/test/ActsValidateOrthogonalSeeds.sh
🟢	run_ci_tests: ../athena/AtlasTest/CITest/test/ActsValidateClusters.sh
🟢	run_ci_tests: ../athena/AtlasTest/CITest/test/ActsPersistifyEDM.sh
🟢	run_ci_tests: ../athena/AtlasTest/CITest/test/ActsGSFRefitting.sh
🟢	run_ci_tests: ../athena/AtlasTest/CITest/test/ActsKfRefitting.sh
🟢	run_ci_tests: python3 ../athena/Tracking/Acts/ActsGeometry/test/ActsExtrapolationAlgTest.py
🟢	run_ci_tests: python3 ../athena/Tracking/Acts/ActsGeometry/test/ActsITkTest.py
🟢	run_workflow_tests_run4_mc
🟢	run_workflow_tests_run2_data
🟢	run_workflow_tests_run3_mc
🟢	run_workflow_tests_run3_data