refactor: only use shaping dialer for ndt7 and dash (#754)

See https://github.com/ooni/probe/issues/2112 for context.

While there, run `go fix -fix buildtag ./...`

internal/netxlite/shaping_otherwise.go

@@ -0,0 +1,11 @@
+//go:build !shaping
+
+package netxlite
+
+import (
+	"github.com/ooni/probe-cli/v3/internal/model"
+)
+
+func newMaybeShapingDialer(dialer model.Dialer) model.Dialer {
+	return dialer
+}