do not show common name text when no common names exist

lib/plantnet/parser.ex

@@ -82,7 +82,7 @@ defmodule PlantIdDiscordBot.PlantNet.Parser do
     best_result_iucn_category = best_result["iucn"]["category"]
     score = round(best_result["score"] * 100) |> Integer.to_string()
 
-    "My best guess is **#{best_guess_name}** with a confidence of **#{score}%**. Common names include **#{Enum.join(best_result["species"]["commonNames"], ", ")}**.\n\nSpecies info from plant databases:\n[GBIF](<#{best_result["gbif_url"]}>) | [PFAF](<#{best_result["pfaf_url"]}>) | [POWO](<#{best_result["powo_url"]}>)#{if best_result_iucn_category, do: "\n\nConservation status: #{iucn_parser(best_result_iucn_category)}"}#{get_alternatives(other_results)}"
+    "My best guess is **#{best_guess_name}** with a confidence of **#{score}%**.#{get_common_names(best_result)}\n\nSpecies info from plant databases:\n[GBIF](<#{best_result["gbif_url"]}>) | [PFAF](<#{best_result["pfaf_url"]}>) | [POWO](<#{best_result["powo_url"]}>)#{if best_result_iucn_category, do: "\n\nConservation status: #{iucn_parser(best_result_iucn_category)}"}#{get_alternatives(other_results)}"
   end
 
   @spec generate_gbif_url(map()) :: map()
@@ -112,7 +112,17 @@ defmodule PlantIdDiscordBot.PlantNet.Parser do
     end)
   end
 
-  @spec get_alternatives(map()) :: String.t()
+  @spec get_common_names(map()) :: String.t()
+  defp get_common_names(data) do
+    common_names = data["species"]["commonNames"]
+
+    if length(common_names) > 0 do
+      " Common names include **" <>
+        Enum.join(common_names, ", ") <> "**."
+    end
+  end
+
+  @spec iucn_parser(String.t()) :: String.t()
   defp iucn_parser(abbreviation) do
     case abbreviation do
       "DD" -> "Data Deficient"
@@ -128,6 +138,7 @@ defmodule PlantIdDiscordBot.PlantNet.Parser do
     end
   end
 
+  @spec get_alternatives(map()) :: String.t()
   defp get_alternatives(data) do
     if length(data) > 0 do
       alternatives =