Starting today vcpkg wants to rebuild GnuTLS but fails:
```
error: building shiftmedia-libgnutls:x64-windows failed with: BUILD_FAILED
```
Ref: https://github.com/curl/curl/actions/runs/10594890318/job/29359499149#step:5:144
Temporary solution:
- drop it from the MultiSSL job.
- replace with mbedTLS job. This job still tests libssh and I could
not find a better place for it right away.
GnuTLS to be restored once it builds again. Possibly when this hash
reaches the GHA `windows-latest` runner:
f5ec6f30ff
Also:
- switch to Debug for the mbedTLS job. Should also work now with
GnuTLS, once it's back:
Ref: https://github.com/microsoft/vcpkg/pull/40473Closes#14710
a5682d9cb9