🔧(react) fix types file broken imports

Generated types for the react package were broken because they were
still using absolute imports which cannot work in standalone .d.ts
files because they cannot rely on the local baseUrl compiler option.
Thus, we introduced an alias that we are able to reliably replace
during type generation.

packages/react/tsconfig.json

@@ -2,7 +2,9 @@
   "extends": "@openfun/typescript-configs/react.json",
   "compilerOptions": {
     "noEmit": true,
-    "baseUrl": "./src",
+    "paths": {
+      ":/*": ["./src/*"]
+    },
     "types": ["vitest/globals", "vite/client"]
   },
   "include": ["src", "cunningham.ts"],