[Refactor] remove orphaned _experimental/out build artifacts

The previous revert left three files under
_experimental/out/_next/static/8Gn6tA2K4jsPxzCCMwObH/ still staged
(git checkout origin/main -- only restores files present in main, it
does not delete files that exist only on the PR branch). Remove them
so the PR no longer touches _experimental/out/ at all.

litellm/proxy/_experimental/out/_next/static/8Gn6tA2K4jsPxzCCMwObH/_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/8Gn6tA2K4jsPxzCCMwObH/_clientMiddlewareManifest.json

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

litellm/proxy/_experimental/out/_next/static/8Gn6tA2K4jsPxzCCMwObH/_ssgManifest.js

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