address layer performance filter disabled with negative layers

[Peter Johnson]

we have an address layer filter in place to avoid querying the large address layer when it's not required (input too long, missing the required components, etc).

with the introduction of #1525 it seems that this filter is incorrectly circumvented when providing a negative layer configuration in the query params, such as: layers=-empire.

I suspect whats happening here is internally layers=DIFFERENCE(['empire'], auto_discover_layers) and so therefore includes address which in turn disables the filter mechanism.