Handle term box (StorageException) for deleted revisions

We need to handle StorageException in EntityViewPlaceholderExpander,
and not display the term box.

It's a bit too involved and probably not what we want to
have WikiPageEntityLookup handle deleted revisions for this.

Also added test for this and cleaned up the tests somewhat.

Bug: 66346
Change-Id: Ia8d8c814c1b03ecb94e0c1af229680309680922b
Merge "Handle term box (StorageException) for deleted revisions"