clan-vm-manager: remove type assertions

we use mypy already, so these type assertions don't make sense.
Also we no longer have strings and always FlakeId in this case

pkgs/clan-vm-manager/clan_vm_manager/singletons/use_vms.py

@@ -110,12 +110,8 @@ class ClanStore:
         def log_details(gfile: Gio.File) -> None:
             self.log_details(vm, gfile)
 
-        assert isinstance(entry.flake.flake_url, FlakeId)
-
         vm = VMObject(icon=icon, data=entry, build_log_cb=log_details)
-        assert isinstance(vm.data.flake.flake_url, FlakeId)
         self.push(vm)
-        assert isinstance(vm.data.flake.flake_url, FlakeId)
 
     def log_details(self, vm: VMObject, gfile: Gio.File) -> None:
         views = ViewStack.use().view