Fix test failure for "dotnet mysql client" by updating the MySqlClient
project from net5.0 to net8.0 target framework. This aligns with the
.NET 8.0 SDK installed in the Docker environment.
The MySqlConnector test was already working, but MySqlClient was still
targeting the old framework version.
🤖 Generated with [Claude Code](https://claude.ai/code)
Co-Authored-By: Claude <noreply@anthropic.com>
elianddb