message: fix: ensure individual column names accepted in output-columns-selection
  Followup of
  Ensures that columns names are accepted in `--output-columns-selection` CLI flag, by removing the constraint in clap config.
diff: @@ -514,7 +514,6 @@ pub struct NextcladeRunOutputArgs {
  use_value_delimiter = true
  )]
  #[clap(requires = "tabular_output")]
  - #[clap(possible_values=CSV_POSSIBLE_CATEGORIES.iter().map(String::as_str))]
  pub output_columns_selection: Vec<String>,
  /// Path to output phylogenetic tree with input sequences placed onto it, in Auspice JSON V2 format.
  