cmd/tailscale: use tailnet display name on cli (#17079)

Updates cli to use tailnet display name

Updates tailscale/corp#32108

Signed-off-by: nikiUppal-TS <nikita@tailscale.com>

ipn/prefs.go

@@ -5,6 +5,7 @@ package ipn
 
 import (
 	"bytes"
+	"cmp"
 	"encoding/json"
 	"errors"
 	"fmt"
@@ -1001,6 +1002,13 @@ func (n NetworkProfile) RequiresBackfill() bool {
 	return n == NetworkProfile{}
 }
 
+// DisplayNameOrDefault will always return a non-empty string.
+// If there is a defined display name, it will return that.
+// If they did not it will default to their domain name.
+func (n NetworkProfile) DisplayNameOrDefault() string {
+	return cmp.Or(n.DisplayName, n.DomainName)
+}
+
 // LoginProfile represents a single login profile as managed
 // by the ProfileManager.
 type LoginProfile struct {