Remove unnecessary rescan after copying file

[KoBeWi]

Fixes #101290

The bug is caused by ProgressDialog manual iteration that makes scan run during importing. Not sure if it's a correct fix though.

[Hilderin]

I'm concerned a bit with this solution because it does not really prevent 2 scans to be executed at the same time. 2 scans at the same time could lead to a corruption of EditorFileSystem::filesystem.

I think the real issue is that a scan is started in FileSystemDock::_move_operation_confirm when is_copied is true at line 1972 while _try_duplicate_item and EditorFileSystem::copy_file queued a refresh_filesystem in EditorFileSystem.
Then, we have 2 scans running at the same time.

First, I think the rescan in FileSystemDock::_move_operation_confirm is useless following #97090. I tested, and just that fixes the issue.

Second, I think to avoid this problem elsewhere in the future, a much global way to fix that should be to prevent 2 scans at the same time. I suggest:

• Adding a check on refresh_queued In EditorFileSystem::scan() and EditorFileSystem::scan_changes to skip the scan if a refresh is queued.
• Adding a check on if (scanning || scanning_changes || thread.is_started()) { in EditorFileSystem::_refresh_filesystem
• Adding a check on refresh_queued In EditorFileSystem::_notification() in case NOTIFICATION_PROCESS, exactly like the prevent_recursive_process_hack.

I created a proof of concept PR the test my hypothesis: master...Hilderin:godot:fix-double-scan-file-system

[KoBeWi]

Changed to a different fix as suggested.

[Hilderin]

Tested locally and that fixes the issue. Not sure the extra suggested checks are necessary for now, so that's ok.