Override public clone_repo_contents instead of private helper

npm_and_yarn/lib/dependabot/npm_and_yarn/file_fetcher.rb

@@ -30,24 +30,26 @@ def self.required_files_message
         "Repo must contain a package.json."
       end
 
-      private
-
       # Overridden to pull any yarn data or plugins which may be stored with Git LFS.
-      def _clone_repo_contents(target_directory:)
-        path = super(target_directory: target_directory)
+      def clone_repo_contents
+        return @git_lfs_cloned_repo_contents_path if defined?(@git_lfs_cloned_repo_contents_path)
+
+        @git_lfs_cloned_repo_contents_path = super
         begin
           SharedHelpers.with_git_configured(credentials: credentials) do
-            Dir.chdir(path) do
+            Dir.chdir(@git_lfs_cloned_repo_contents_path) do
               cache_dir = Helpers.fetch_yarnrc_yml_value("cacheFolder", "./yarn/cache")
               SharedHelpers.run_shell_command("git lfs pull --include .yarn,#{cache_dir}")
             end
-            path
+            @git_lfs_cloned_repo_contents_path
           end
         rescue StandardError
-          path
+          @git_lfs_cloned_repo_contents_path
         end
       end
 
+      private
+
       def fetch_files
         fetched_files = []
         fetched_files << package_json