(bugfix) get/import: fix broken progress bar (#4039)

PR #3672 (6d8499e) extended `LocalRemote::_get_plans` to return one
`checksums` too. As all of the args from `_get_plans` was passed
down to `download()`, it recognized extra arg of checksum as
`no_progress_bar` due to which it became True and stopped showing
progress bar at all.

Fix #3874

dvc/remote/local.py

@@ -626,8 +626,12 @@ def _process(
             func = pbar.wrap_fn(func)
             with ThreadPoolExecutor(max_workers=jobs) as executor:
                 if download:
-                    fails = sum(executor.map(func, *dir_plans))
-                    fails += sum(executor.map(func, *file_plans))
+                    from_infos, to_infos, names, _ = (
+                        d + f for d, f in zip(dir_plans, file_plans)
+                    )
+                    fails = sum(
+                        executor.map(func, from_infos, to_infos, names)
+                    )
                 else:
                     # for uploads, push files first, and any .dir files last