chore: align _experimental/out UI build with internal_staging

The revert of 62df632 restored an older Next.js build state. Many of
those build artifacts were not in internal_staging, so they survived
the merge as pure additions, polluting the PR diff with ~140 generated
files. Realigning to internal_staging's build keeps the PR focused on
real code changes.

litellm/proxy/_experimental/out/_next/static/aKKihXXKRJWLQThZgi8Rq/_buildManifest.js

@@ -1,16 +0,0 @@
-self.__BUILD_MANIFEST = {
-  "__rewrites": {
-    "afterFiles": [],
-    "beforeFiles": [
-      {
-        "source": "/litellm-asset-prefix/_next/:path+",
-        "destination": "/_next/:path+"
-      }
-    ],
-    "fallback": []
-  },
-  "sortedPages": [
-    "/_app",
-    "/_error"
-  ]
-};self.__BUILD_MANIFEST_CB && self.__BUILD_MANIFEST_CB()

litellm/proxy/_experimental/out/_next/static/aKKihXXKRJWLQThZgi8Rq/_clientMiddlewareManifest.json

@@ -1 +0,0 @@
-[]

litellm/proxy/_experimental/out/_next/static/aKKihXXKRJWLQThZgi8Rq/_ssgManifest.js

@@ -1 +0,0 @@
-self.__SSG_MANIFEST=new Set([]);self.__SSG_MANIFEST_CB&&self.__SSG_MANIFEST_CB()