Add enterprise license loading to the example

[mihaitodor]

Users will have to do the following if they wish to use enterprise components in custom builds:

package main

import (
	"context"

	"github.com/redpanda-data/benthos/v4/public/service"
	"github.com/redpanda-data/connect/v4/public/license"

	// Import full suite of FOSS and Enterprise connect components
	_ "github.com/redpanda-data/connect/public/bundle/enterprise/v4"
)

func main() {
	service.RunCLI(context.Background(),
		service.CLIOptOnConfigParse(func(pConf *service.ParsedConfig) error {
			license.LocateLicense(pConf.Resources())
			return nil
		}),
	)
}