[FIX] BlockEntry constructor fails for hidden title
[FIX] BlockEntry constructor fails for hidden title

- return an empty dict if 'param' is missing; test for old behaviour first
- use an empty string for autoblock detection if title is hidden
- return an empty list id 'params' (and 'flags') is missing

Bug: T78152
Change-Id: Icaf80ed270b2fa8ffa6f2519539a47313cabc7a2

wikimedia/pywikibot-core,wikimedia/pywikibot-core