Always allow custom wildcards

Removed unnecessary restriction that custom wildcards are only possible when ``'before'`` and ``'after'`` are ``false`` (disabled).
This allows queries like:
``Text LIKE '%This _s _ T%t%'``, when ``"This ?s ? T*t"`` was entered as search query, while ``'before'`` and ``'after'`` are ``true``.
One or the other can be false, too