ERP5Type/patches: simplify default_zpublisher_encoding patch

Instead of doing what loading zope.conf does (which is different
across zope versions), use the ZConfig configuration callback.
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passed ERP5.CodingStyleTest-Master

00:46:35

passed ERP5.UnitTest-Master

01:22:36

failed ERP5.UnitTest-Master.Medusa

01:24:15

passed SlapOS.Eggs.UnitTest-Master.Python3

00:13:02