Fix facet title

[Richèl Bilderbeek]

The facet titles are reversed:

[Richèl Bilderbeek]

Look what I spot here:

    inference_model_labels <- c("Best", "Generative")
    names(inference_model_labels) <- c("Generative", "Best")

[Richèl Bilderbeek]

This was caused by replacing this (which did not use a factor):

    medians$inference_model <- gsub(
      x = gsub(
        x = medians$tree_and_model,
        pattern = "true_",
        replacement = ""
      ),
      pattern = "twin_",
      replacement = ""
     )

to something that does use a factor:

    medians$inference_model <- forcats::fct_collapse(
      medians$tree_and_model,
      generative = c("true_generative", "twin_generative"),
      candidate = c("true_candidate", "twin_candidate")
    )