Removing conda exception for activation in Windows

[ryanskeith]

Description

Partially fixes issue #6069 (other changes needed to take place in another repository (namely conda). Windows will now be inline with what the other platforms do. See issue for more background.

Changes

• Removed conda clause from windows activation check
• Moved the check from m.config.activate -> m.activate_build_script (which brings Windows inline with other platforms)
  • Just as an FYI, activate_build_script -> m.conda.activate and self.get_value("build/activate_in_script") is not False
• Added parametrized tests

Checklist - did you ...

• Add a file to the news directory (using the template) for the next release's release notes?
• Add / update necessary tests?
• Add / update outdated documentation?

[codspeed-hq]

Merging this PR will not alter performance

✅ 5 untouched benchmarks

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_{Comparing fix-windows-skips-with-conda (fb9eaa4) with main (3b6a390)}