Heat the oil over medium heat in a large skillet. Add the pancetta and cook about 3 minutes per side, until crispy. Leaving the fat in the skillet, transfer the pancetta to a plate. Add the radishes, vinegar, and honey to the skillet, and simmer over low heat. Season with salt and pepper. Cook until the radishes are crisp-tender and glazed, about 10 minutes. Add the lemon juice and stir to combine. Transfer the radishes and liquids from the pan into the bowl of farro. Add the celery, celery leaves, and goat cheese. Crumble the pancetta on top and toss to combine. Season to taste with salt and pepper. Serve.