add can_unschedule to PagePermissionTester

wagtail/admin/views/pages.py

@@ -1154,7 +1154,7 @@ def revisions_unschedule(request, page_id, revision_id):
     page = get_object_or_404(Page, id=page_id).specific
 
     user_perms = UserPagePermissionsProxy(request.user)
-    if not user_perms.for_page(page).can_publish():
+    if not user_perms.for_page(page).can_unschedule():
         raise PermissionDenied
 
     revision = get_object_or_404(page.revisions, id=revision_id)

wagtail/core/models.py

@@ -1759,6 +1759,9 @@ class PagePermissionTester:
     def can_set_view_restrictions(self):
         return self.can_publish()
 
+    def can_unschedule(self):
+        return self.can_publish()
+
     def can_lock(self):
         return self.user.is_superuser or ('lock' in self.permissions)