There are two underlying issues which got uncovered by the report:
First, is that the poll() function for the operator was using legacy
API which is on its way of removal in the next major version release.
This part is fixed in this patch based on a patch provided by Philipp
Oeser (P3389) with the modification that the `clip` is not accessed
prior to None check. Ended up in a bit annoying one-liner, the entire
function could be refactored to use early returns.
The second issue is that the Python access to the legacy property
was wrong: need to access camera reconstruction instead of accessing
deprecated DNA field.