Make internal redispatch-condition consistent

[markusbaumeister]

Currently, the package contains an internal bool SIMPLICIAL_ENABLE_SURFACE_REDISPATCH. It can be used to disable the expensive redispatch computing umbrellas.

All RedispatchOnCondition that try to make a complex into a surface should be conditional on that parameter. Other redispatches should work generally. There is currently one redispatch in graphs.gi that is inside such a conditional although it should not be.