net/dns/recursive: set EDNS on queries

Updates tailscale/corp#30631

Change-Id: Ib88ea1bb51dd917c04f8d41bcaa6d59b9abd4f73
Signed-off-by: Brad Fitzpatrick <bradfitz@tailscale.com>
This commit is contained in:
Internal Server Error - Gitea: Git with a cup of tea
500 Internal Server Error

Gitea Version: 1.28.0+dev-477-g8b6ad49a5f