types/ptr: deprecate ptr.To, use Go 1.26 new

Updates #18682

Change-Id: I62f6aa0de2a15ef8c1435032c6aa74a181c25f8f
Signed-off-by: Brad Fitzpatrick <bradfitz@tailscale.com>

ipn/lapitest/server.go

@@ -22,7 +22,6 @@ import (
 	"tailscale.com/ipn/ipnserver"
 	"tailscale.com/types/logger"
 	"tailscale.com/types/logid"
-	"tailscale.com/types/ptr"
 	"tailscale.com/util/mak"
 	"tailscale.com/util/rands"
 )
@@ -153,7 +152,7 @@ func (s *Server) MakeTestActor(name string, clientID string) *ipnauth.TestActor
 	}
 
 	// Create a shallow copy of the base actor and assign it the new client ID.
-	actor := ptr.To(*baseActor)
+	actor := new(*baseActor)
 	actor.CID = ipnauth.ClientIDFrom(clientID)
 	return actor
 }