To fix building tests/server with cmake and both wolfSSL and OpenSSL
enabled (MultiSSL).
tests/server do not have libcurl dependency header paths setup because
it does not use libcurl. The code however includes `curl_setup.h`, which
tried including `wolfssl/version.h` before this patch to verify if the
wolfSSL coexist feature is available. Without a header path, it failed:
```
In file included from bld/tests/server/servers.c:3:
In file included from tests/server/first.h:40:
lib/curl_setup.h:737:12: fatal error: 'wolfssl/version.h' file not found
737 | # include <wolfssl/version.h>
| ^~~~~~~~~~~~~~~~~~~
1 error generated.
```
Ref: https://github.com/curl/curl/actions/runs/22410066319/job/64880787424#step:46:76
Fix by moving the include and version check to `vtls/wolfssl.c`.
Also: add an early version check to cmake.
Follow-up to 16f073ef49#16973
Cherry-picked from #20720Closes#20726