fix nextjs sourcemap upload 404 (#12012)

closes #12004

Author: a-hariti

redirects.js

@@ -218,6 +218,10 @@ const userDocsRedirects = [
     source: '/organization/integrations/launchdarkly/',
     destination: '/organization/integrations/feature-flag/launchdarkly/',
   },
+  {
+    source: '/platforms/javascript/guides/nextjs/sourcemaps/uploading/',
+    destination: '/platforms/javascript/guides/nextjs/sourcemaps/',
+  },
   {
     source: '/organization/integrations/vercel/',
     destination: '/organization/integrations/deployment/vercel/',