fix: copy files dir in importTrace only if output folder different from input one

it seems that if they are the same, the copy leaves the files empty in the
target folder: i assume behaviour of copy dir no recursive

Author: alehander92

src/ct/trace/storage_and_import.nim

@@ -172,7 +172,8 @@ proc importTrace*(
         break # for now assume the first detected lang is ok
 
   if dirExists(traceFolder / "files"):
-    copyDir(traceFolder / "files", outputFolder / "files")
+    if traceFolder != outputFolder:
+      copyDir(traceFolder / "files", outputFolder / "files")
   elif selfContained and downloadUrl == "":
     # for now assuming if no `files/` dir already,
     # it happens on the original machine