Merge Request diffs console error - `oldSha` invalid Vue prop
Description
Noticed on master
on the seed MR /twitter/typeahead-js/-/merge_requests/1
... When opening the Merge Request diff the following console error shows up a bunch
[Vue warn]: Invalid prop: type check failed for prop "oldSha". Expected String with value "null", got Null
found in
---> <DiffViewer> at vue_shared/components/diff_viewer/diff_viewer.vue
<DiffContent> at diffs/components/diff_content.vue
<DiffFile> at diffs/components/diff_file.vue
<DiffsApp> at diffs/components/app.vue
<Root>