Fix MatchingOptional property

[Baptouuuu]

Problem

In the CI when this property is run in a sequence of properties it randomly fails.

After investigation the query run is not(endsWith) opposed to the equality from previous queries in the same property. This is a bad copy/paste from another property, the aimed query was not(equality).

When checking the documentation of Elasticsearch it's indicated that a wildcard query starting with *, which is what endsWith is translated to, is an expensive query that should be avoided.

Solution

• Fix property to use not(equality)
• Add a Known issues chapter in the documentation