Fix Attribute Error in Upgrade Step 2619

[ramonski]

Description of the issue/feature this PR addresses

This PR handles the following error in Upgrade Step 2619 that was introduced in #2537:

Traceback (innermost last):
  Module ZPublisher.WSGIPublisher, line 176, in transaction_pubevents
  Module ZPublisher.WSGIPublisher, line 385, in publish_module
  Module ZPublisher.WSGIPublisher, line 288, in publish
  Module ZPublisher.mapply, line 85, in mapply
  Module ZPublisher.WSGIPublisher, line 63, in call_object
  Module Products.GenericSetup.tool, line 1135, in manage_doUpgrades
  Module Products.GenericSetup.upgrade, line 185, in doStep
  Module senaite.core.upgrade.v02_06_000, line 2192, in setup_result_types
AttributeError: 'NoneType' object has no attribute 'get'

Current behavior before PR

Traceback occurs due to a false indexed object in the UID catalog

Desired behavior after PR is merged

Error is handled gracefully and an error log is printed

--
I confirm I have tested this PR thoroughly and coded it according to PEP8
and Plone's Python styleguide standards.