feat: Rspack support config.experimental.useLightningcss to switch css-minimizer-plugin (#79928)
Rspack support config.experimental.useLightningcss to switch
css-minimizer-plugin.
Rspack using LightningCssMinimizerRspackPlugin by default.
If users encounter some CSS issues, they can switch back to the
css-minimizer-plugin through `config.experimental.useLightningcss:
false`.
In test mode, Rspack uses css-minimizer-plugin for compatibility.