docs: fix sitemap of ui docs (#11928)

www/apps/ui/src/app/sitemap.ts

@@ -0,0 +1,14 @@
+import { retrieveMdxPages } from "build-scripts"
+import type { MetadataRoute } from "next"
+import path from "path"
+import { siteConfig } from "../config/site"
+import { basePathUrl } from "../lib/base-path-url"
+
+export default function sitemap(): MetadataRoute.Sitemap {
+  return retrieveMdxPages({
+    basePath: path.resolve("src", "content", "docs"),
+    testFileName: false,
+  }).map((filePath) => ({
+    url: `${siteConfig.baseUrl}${basePathUrl(filePath)}`,
+  }))
+}

www/apps/ui/src/app/sitemap.xml

@@ -1,9 +0,0 @@
-<?xml version="1.0" encoding="UTF-8"?>
-<sitemapindex xmlns="http://www.sitemaps.org/schemas/sitemap/0.9">
-  <sitemap>
-    <loc>https://docs.medusajs.com/ui/assets/sitemap.xml</loc>
-  </sitemap>
- <sitemap>
-    <loc>https://docs.medusajs.com/sitemap-docs.xml</loc>
-  </sitemap>
-</sitemapindex>