chore!: remove unused files part 2 (#5282)

Deletes the unused files that are detected in:
- #5075
and have been missed in:
- #5074

I would suggest to add them for now to the ignore list in the unused file check and remove the entries with this PR together with the files. Therefore blocked by:
- #5075

### `Core/include/Acts/EventData/detail/ParameterTraits.hpp`

This one is ancient. Hasn't been updated for 6 years. It was missed in the file check, because `Core/include/Acts/Propagator/Propagator.hpp` included `ParameterTraits` from `Core/include/Acts/Propagator/detail/ParameterTraits.hpp`. This was removed in:
- #5240

### `Core/include/Acts/Seeding/PathSeeder.hpp`

This was only used by `Tests/UnitTests/Core/Seeding/PathSeederTest.cpp`, which was removed in:
- #5261

### `Tests/CommonHelpers/include/ActsTests/CommonHelpers/TestSpacePoint.hpp`

This was only used by `Tests/UnitTests/Core/SpacePointFormation/SpacePointBuilderTests.cpp`, which was removed in:
- #5261

Author: AJPfleger

CI/check_unused_files.py

@@ -83,10 +83,6 @@
     # Python uv files
     "Detray/codegen/detray-sympy/uv.lock",
     "Detray/python/detray/uv.lock",
-    # Temporarily excluded files. TODO remove in next major release.
-    "Core/include/Acts/EventData/detail/ParameterTraits.hpp",
-    "Core/include/Acts/Seeding/PathSeeder.hpp",
-    "Tests/CommonHelpers/include/ActsTests/CommonHelpers/TestSpacePoint.hpp",
 )
 SUFFIX_CPP = (
     ".hpp",