Patch Changes

• af70c87: Add a deleted_classes: ["UserDetails"] Durable Object migration to the graphql server.

  #384 removed the UserDetails Durable Object (and its bindings) from every server, and added the
  required delete-class migration to the two servers that own the class (workers-observability,
  workers-builds). The graphql worker's already-deployed version still depends on UserDetails, so
  wrangler deploy rejected the new version with code: 10064 ("New version of script does not export
  class 'UserDetails' which is depended on by existing Durable Objects"), which aborted the staging and
  production deploys. Adding the delete-class migration lets graphql deploy and releases the binding that
  was blocking workers-observability from applying its own deleted_classes migration (code: 10061).

  Validated on staging: graphql + observability deploy cleanly and the staging UserDetails namespace is
  removed.