R1:bc4f86d27996

When a new, deleted, draft inline is revived with "Undo", undelete it

Summary:
See PHI1876. Normally, deleted inlines are undeleted with an "undelete" operation, which clears the "isDeleted" flag.

However, when an inline is deleted implicitly by using "Cancel" without first saving it, the flag currently isn't cleared properly. This can lead to cases where inlines seem to vanish (they are shown to the user in the UI, but treated as deleted on submission).

Test Plan:
There are two affected sequences here…