Qt VLM dialog pretends to support VLM schedules but doesn't really
Forked from #17839:
I can export and import multiple VLM broadcast items with GUI. However, if you add a schedule item, it is not displayed in GUI if you close and reopen the VLM window, or if you load a VLM conf file. But it will be loaded internally : telnet vlm show command displays it.
Indeed the VLMDialog::mediasPopulator() populates only VLM media, not schedules. However contrary to media, there is no proper core API to list VLM schedules: see #25125
So the Qt VLM dialog is hardly at fault for not supporting this. But it is at fault for a misleading and confusing UX.