Make index_url_name and edit_url_name in generic HistoryView optional

Also update the generic UsageView's get_edit_url method signature to
match the HistoryView and the generic IndexView by taking an "instance"
parameter, just to be consistent even though we technically only use
self.object for these views.

wagtail/admin/views/generic/history.py

@@ -226,21 +226,30 @@ class HistoryView(PermissionCheckedMixin, BaseObjectMixin, BaseListingView):
         return str(self.object)
 
     def get_breadcrumbs_items(self):
-        return self.breadcrumbs_items + [
-            {
-                "url": reverse(self.index_url_name),
-                "label": capfirst(self.model._meta.verbose_name_plural),
-            },
-            {
-                "url": self.get_edit_url(self.object),
-                "label": str(self.object),
-            },
+        items = []
+        if self.index_url_name:
+            items.append(
+                {
+                    "url": reverse(self.index_url_name),
+                    "label": capfirst(self.model._meta.verbose_name_plural),
+                }
+            )
+        edit_url = self.get_edit_url(self.object)
+        if edit_url:
+            items.append(
+                {
+                    "url": edit_url,
+                    "label": str(self.object),
+                }
+            )
+        items.append(
             {
                 "url": "",
                 "label": gettext("History"),
                 "sublabel": self.get_page_subtitle(),
-            },
-        ]
+            }
+        )
+        return self.breadcrumbs_items + items
 
     @cached_property
     def header_buttons(self):

wagtail/admin/views/generic/usage.py

@@ -38,9 +38,9 @@ class UsageView(PermissionCheckedMixin, BaseObjectMixin, BaseListingView):
             return object.get_latest_revision_as_object()
         return object
 
-    def get_edit_url(self):
+    def get_edit_url(self, instance):
         if self.edit_url_name:
-            return reverse(self.edit_url_name, args=(quote(self.object.pk),))
+            return reverse(self.edit_url_name, args=(quote(instance.pk),))
 
     def get_usage_url(self, instance):
         if self.usage_url_name:
@@ -61,7 +61,7 @@ class UsageView(PermissionCheckedMixin, BaseObjectMixin, BaseListingView):
                     "label": capfirst(self.object._meta.verbose_name_plural),
                 }
             )
-        edit_url = self.get_edit_url()
+        edit_url = self.get_edit_url(self.object)
         if edit_url:
             items.append(
                 {
@@ -80,7 +80,7 @@ class UsageView(PermissionCheckedMixin, BaseObjectMixin, BaseListingView):
 
     @cached_property
     def header_buttons(self):
-        edit_url = self.get_edit_url()
+        edit_url = self.get_edit_url(self.object)
         buttons = []
         if edit_url:
             buttons.append(