chore: umd version will try to reuse global @ant-design/cssinjs first (#46009)

* chore: alias of it

* chore: comment

alias/cssinjs.js

@@ -0,0 +1,19 @@
+/* eslint-disable global-require, import/no-unresolved */
+
+// This is a alias proxy, which will use global `@ant-design/cssinjs` first.
+// Use local if global not found.
+let cssinjs;
+
+if (typeof window !== 'undefined' && window.antdCssinjs) {
+  // Use window UMD version
+  cssinjs = window.antdCssinjs;
+} else if (typeof global !== 'undefined' && global.antdCssinjs) {
+  // Use global UMD version
+  cssinjs = global.antdCssinjs;
+} else {
+  // Use local version.
+  // Use relative path since webpack will also replace module here.
+  cssinjs = require('../node_modules/@ant-design/cssinjs');
+}
+
+module.exports = cssinjs;