fix(test): use non-bang File.rm_rf to avoid race in concurrent score-dir cleanup

test/support/data_case.ex

@@ -62,7 +62,10 @@ defmodule Microwaveprop.DataCase do
   """
   def reset_score_files do
     dir = Application.get_env(:microwaveprop, :propagation_scores_dir)
-    if is_binary(dir), do: File.rm_rf!(dir)
+
+    if is_binary(dir) do
+      File.rm_rf(dir)
+    end
   end
 
   @doc """