curl_setup.h: move UWP detection after `config-win32.h` (revert)

curl_setup.h: move UWP detection after `config-win32.h` (revert)

This change wasn't good because `config-win32.h` does rely on the UWP
detection result to set `USE_WIN32_CRYPTO` and LDAP macros. While it
fixed one issue, it created another.

It seems better to revert, and focus on reducing and/or eventually
dropping the logic within `config-win32.h` that alters `_WIN32_WINNT`.
It may not be necessary anymore with a minimum of VS2008 (soon VS2010).
The logic is also absent from cmake builds, without causing issues.

Could affect UWP winbuild/project-file builds. These are theoretical
builds because neither build method is prepared to target UWP.

Reverts 792a61e2047782b85da0332cf298a747ce11e8e6 #17980
Ref: https://github.com/curl/curl/pull/17980#issuecomment-3114462492

Closes #18014