BUG: Fix PythonVerifyGetOutputAPIConsistency test on Windows

[tbirdso]

#3156 introduced a Python mechanism for loading object factory overrides alongside modules at load time. load_factories is an implementation detail and may not be suitable to be called directly.

Issue #3261 exhibits an instance of this where a few templates such as _Num_base are not loaded correctly into the itk namespace when load_factories is called by the client program before other modules are loaded. Removing the load_factories() call and relying on force_load() to instead load in both modules and factories results in successful namespace population.

Resolves #3261.

PR Checklist

• Added test (or behavior not changed)

Refer to the ITK Software Guide for
further development details if necessary.

[tbirdso]

Note that this will address one of three test failures we are seeing in the ITK main branch, with the other two unrelated to factory changes: CDash

[thewtex]

Thanks for the CDash / CI attention @tbirdso !!

[tbirdso]

Checking ITK.Linux and ITK.Windows CI status shows that each check completed successfully but failed to POST results to Github due to "Internal Server Error". Perhaps more Github service issues today?

As all checks have passed I am moving forward with the merge.

[PranjalSahu]

Two checks failing on windows python for mesh serialization and pointset serialization.
Working on it.

[tbirdso]

@PranjalSahu I've also glanced through the serialization failures, they are due to inconsistencies in how we wrap VectorContainer across platforms and not directly due to any serialization issues. I've opened #3310 for discussion.