Fix 5.29 regression using temp tables

Fix 5.29 regression using temp tables

I just pushed 5.29rc through our WMF CI & it failed on a situation where it created a temp
table and that got joined on a non-temp table with a collation mix error. The issue is that the
DB default is set to utf8_general_ci (at least on our development DBs) whereas the
civicrm tables are utf8_unicode_ci. Until https://github.com/civicrm/civicrm-core/pull/18012/files
there was a list of permitted matches for db collation but now any 'utf' string matches.

From what I can tell utf8_general_ci  is a pretty common collation on drupal DBs and from my tests
it causes problems if not excluded here