Weaken type requirements of `pluggin_settings` fields

[aaraney]

ngen-cal/python/ngen_cal/src/ngen/cal/model.py

Line 271 in 2823b2c

plugin_settings: Dict[str, Dict[str, Any]] = Field(default_factory=dict)

I don't see a reason why this shouldnt be pluggin_settings: Dict[str, Any]. This should be changed for both model and general plugins.