- GHA/windows: switch mingw-w64 UWP CI job to use UCRT.
`msvcr120_app` was missing `getch()` for example.
Follow-up to f988842d85#15637
This job tests compiling for UWP correctly, but the the resulting
`curl.exe` still doesn't look like a correct UWP app, now exiting
on startup with: `curl: error initializing curl library`.
- tool_getpass: restore `getch()` for UWP builds.
Follow-up to f988842d85#15637
- schannel: silence `-Werror=null-dereference` warning in mingw-w64 UWP:
```
lib/vtls/schannel_verify.c: In function 'Curl_verify_host':
lib/vtls/schannel_verify.c:558:33: error: null pointer dereference [-Werror=null-dereference]
558 | for(i = 0; i < alt_name_info->cAltEntry; ++i) {
| ~~~~~~~~~~~~~^~~~~~~~~~~
lib/vtls/schannel_verify.c:559:50: error: null pointer dereference [-Werror=null-dereference]
559 | PCERT_ALT_NAME_ENTRY entry = &alt_name_info->rgAltEntry[i];
| ~~~~~~~~~~~~~^~~~~~~~~~~~
```
Ref: https://github.com/curl/curl/actions/runs/12022656065/job/33515255397?pr=15638#step:19:27
Follow-up to 9640a8ef6f#15421
- GHA/windows: fix `find` command in MSVC job step.
Follow-up to 5f9411f953#15380
- GHA/windows: drop unnecessary `windowsappcompat` lib from mingw-w64
UWP job. Also drop related MSYS2 package.
- GHA/windows: cmake 3.31.0 still invokes `windres` with wrong options
with mingw-w64 UPW. Update curl version in comment accordingly.
- GHA/windows: tidy up mingw-w64 UWP spec logic, limit it to gcc.
- GHA/windows: update comments on `curl.exe` UWP startup errors.
Closes#15638
72edb22b8a