win: ship python3t.dll and python3t.lib in GIL-enabled builds

[serjflint]

Fixes #934.

GIL-enabled 3.15 builds already produce python3t.dll, a forwarder to python315.dll, but only the free-threaded build copied it into the package. The shipped pyconfig.h auto-links python3t.lib under Py_TARGET_ABI3T, so this fixes building abi3t extensions as well as loading them.

It goes next to python315.dll, as in the nuget layout. The MSI uses abi3t-compat\ only because it can mix GIL and free-threaded builds in one folder, which a conda env can't.

[conda-forge-admin]

Hi! This is the friendly automated conda-forge-linting service.

I just wanted to let you know that I linted all conda-recipes in your PR (recipe/meta.yaml) and found it was in an excellent condition.

I do have some suggestions for making it better though...

For recipe/meta.yaml:

• ℹ️ The recipe is not parsable by parser conda-souschef (grayskull). This parser is not currently used by conda-forge, but may be in the future. We are collecting information to see which recipes are compatible with grayskull.
• ℹ️ The recipe is not parsable by parser conda-recipe-manager. The recipe can only be automatically migrated to the new v1 format if it is parseable by conda-recipe-manager.

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