Add support for global() function in CSS Modules animation names

[jantimon]

lightningcss localalizes animations for css modules with quite well - for example

Input:

  animation: baz 2s;

Output:

  animation: EgL3uq_baz 2s;

However in some cases we were running into issues with animation names getting localized when we didn't want them to. This is problamatic when using third-party animation libraries or sharing animations across components.

For selectors there is the :global specifier so we added support for a global() function that can be used directly in animation properties to match with postcss-modules-local-by-default: css-modules/postcss-modules-local-by-default#76

Input:

  animation: global(baz) 2s;

Output:

  animation: baz 2s;

The current solution handles the global function in properties/custom.rs but I'm open to moving it if there's a better spot for this logic

Please let me know what you think