Fix showing "Inherit From" info in <gr-repo-access>

We should also show the "Inherit From" input in editing mode, because
as a user has reported: Otherwise the input vanished immediately when
it becomes empty during editing.

Google-Bug-Id: b/214402059
Change-Id: I0d44d7f1a8632ac5ab15e3c43ae08bad27cdce37
diff --git a/polygerrit-ui/app/elements/admin/gr-repo-access/gr-repo-access.ts b/polygerrit-ui/app/elements/admin/gr-repo-access/gr-repo-access.ts
index cf5d952..f8b36c4 100644
--- a/polygerrit-ui/app/elements/admin/gr-repo-access/gr-repo-access.ts
+++ b/polygerrit-ui/app/elements/admin/gr-repo-access/gr-repo-access.ts
@@ -260,7 +260,7 @@
   }
 
   _computeShowInherit(inheritsFrom?: ProjectInfo) {
-    return inheritsFrom?.id?.length ? 'show' : '';
+    return this._editing || inheritsFrom?.id?.length ? 'show' : '';
   }
 
   // TODO(TS): Unclear what is model here, provide a better explanation