ipn/ipnlocal: add tailnet MagicDNS name to ipn.LoginProfile

Start backfilling MagicDNS suffixes on LoginProfiles.

Updates #9286

Signed-off-by: Sonia Appasamy <sonia@tailscale.com>

ipn/ipnlocal/peerapi_test.go

@@ -660,7 +660,7 @@ func TestPeerAPIReplyToDNSQueries(t *testing.T) {
 			netip.MustParsePrefix("0.0.0.0/0"),
 			netip.MustParsePrefix("::/0"),
 		},
-	}).View())
+	}).View(), "")
 	if !h.ps.b.OfferingExitNode() {
 		t.Fatal("unexpectedly not offering exit node")
 	}