Issue #10450 crash or critical using file open options dialog
When opening images like DDS or EPS that have an options dialog, we either get a crash, or criticals.
The critical made clear that there is a problem dereferencing: (gimp-2.99.exe:9900): GLib-CRITICAL **: 14:52:58.831: g_atomic_ref_count_dec: assertion 'old_value > 0' failed
Looking at gimp_file_dialog_progress_get_window_id we see that the handle doesn't get an extra reference, while in other similar places the handle is duplicated.
Using g_bytes_ref on the handle fixes the criticals for me.