[libmysql] Fix libmysql export static library error

[jimwang118]

Fixes #30885
Fix the error of libmysql exporting static library and cause poco installation issue.

CMake Error at F:/vcpkg/installed/x64-windows-static/share/unofficial-libmysql/unofficial-libmysql-targets.cmake:84 (message):
  The imported target "libmysql" references the file

     "F:/vcpkg/installed/x64-windows-static/debug/lib/libmysql.lib"

  but this file does not exist.  Possible reasons include:

  * The file was deleted, renamed, or moved to another location.

  * An install or uninstall procedure did not complete successfully.

  * The installation package was faulty and contained

     "F:/vcpkg/installed/x64-windows-static/share/unofficial-libmysql/unofficial-libmysql-targets.cmake"

  but not all the files it references.

Modify the libmysql port to export mysqlclient.lib during static compilation, and export libmysql.dll during dynamic compilation.

The usage and feature has been tested successfully locally.

find_package(Poco REQUIRED COMPONENTS CppParser)
target_link_libraries(main PRIVATE Poco::CppParser)

• 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.