Fixing crash when reimporting AtlasTextures

The crash was caused by the reimport_files function trying to reimport the atlas file multiple times using multithreading, which caused deadlocks and hang the editor.
This fix prevents files from being added to the reimport_files array if they are already present inside of it.

Fixes godotengine#54817

editor/editor_file_system.cpp

@@ -2078,6 +2078,7 @@ void EditorFileSystem::reimport_files(const Vector<String> &p_files) {
  EditorProgress pr("reimport", TTR("(Re)Importing Assets"), p_files.size());
 
  Vector<ImportFile> reimport_files;
+ Set<String> file_paths_already_seen;
 
  Set<String> groups_to_reimport;
 
@@ -2099,11 +2100,12 @@ void EditorFileSystem::reimport_files(const Vector<String> &p_files) {
  } else if (!group_file.is_empty()) {
  //it's a group file, add group to import and skip this file
  groups_to_reimport.insert(group_file);
- } else {
+ } else if (!file_paths_already_seen.has(file)) {
  //it's a regular file
  ImportFile ifile;
  ifile.path = file;
  ResourceFormatImporter::get_singleton()->get_import_order_threads_and_importer(file, ifile.order, ifile.threaded, ifile.importer);
+ file_paths_already_seen.insert(file);
  reimport_files.push_back(ifile);
  }