TriggerMenuMT: allow Hypo generators to take flags as first argument

Make it possible to pass flags as the first argument to the Hypo generators. The argument has to be named flags, e.g.:

def myToolFromDict(flags, chainDict)

To avoid having to change all HypoTool generators, we inspect the generator function and pass the flags when needed.

cc @fpastore @tbold

Relates to ATR-24994.