[flint] Fix download URL

[tueda]

• Changes comply with the maintainer guide.
• SHA512s are updated for each updated download.
• The "supports" clause reflects platforms that may be fixed by this new version.
• Any fixed CI baseline entries are removed from that file.
• Any patches that are no longer applied are deleted from the port's directory.
• The version database is fixed by rerunning ./vcpkg x-add-version --all and committing the result.
• Only one version is added to each modified port's versions file.

The download page appears to have moved. Refer to: https://flintlib.org/downloads.html.

This patch resolves the following 404 error:

---

Package: flint:[email protected]

Host Environment

• Host: x64-linux
• Compiler: GNU 11.4.0
• vcpkg-tool version: 2025-01-29-a75ad067f470c19f030361064e32a2585392bee2
  vcpkg-scripts version: 344525f 2025-02-13 (4 hours ago)

To Reproduce

vcpkg install flint

Failure logs

Downloading http://www.flintlib.org/flint-2.9.0.zip -> flint-2.9.0.zip
error: curl: (22) The requested URL returned error: 404
note: If you are using a proxy, please ensure your proxy settings are correct.
Possible causes are:
1. You are actually using an HTTP proxy, but setting HTTPS_PROXY variable to `https//address:port`.
This is not correct, because `https://` prefix claims the proxy is an HTTPS proxy, while your proxy (v2ray, shadowsocksr, etc...) is an HTTP proxy.
Try setting `http://address:port` to both HTTP_PROXY and HTTPS_PROXY instead.
2. If you are using Windows, vcpkg will automatically use your Windows IE Proxy Settings set by your proxy software. See: https://github.com/microsoft/vcpkg-tool/pull/77
The value set by your proxy might be wrong, or have same `https://` prefix issue.
3. Your proxy's remote server is our of service.
If you believe this is not a temporary download server failure and vcpkg needs to be changed to download this file from a different location, please submit an issue to https://github.com/Microsoft/vcpkg/issues
CMake Error at scripts/cmake/vcpkg_download_distfile.cmake:124 (message):
  Download failed, halting portfile.
Call Stack (most recent call first):
  ports/flint/portfile.cmake:2 (vcpkg_download_distfile)
  scripts/ports.cmake:196 (include)

[dg0yt]

Fixes #43825.