Remove parameter reference to `availability_estimates` dataframe in HealthSystem

[tamuri]

Noticed whilst looking at objects holding memory that unnecessary reference to availability_estimates, which is dataframe loaded of ResourceFile_Consumables_availability_small.csv, is not needed after Consumables has been initialised.

TLOmodel/src/tlo/methods/healthsystem.py

Lines 660 to 669 in 3599cdc

	# Initialise the Consumables class
	self.consumables = Consumables(
	availability_data=self.update_consumables_availability_to_represent_merging_of_levels_1b_and_2(
	self.parameters['availability_estimates']),
	item_code_designations=self.parameters['consumables_item_designations'],
	rng=rng_for_consumables,
	availability=self.get_cons_availability()
	)

Any reason why this can't be a normal variable in read_parameters?

[tbhallett]

By 'normal variable', you mean something not stored in self.parameters...?

So, in read_parameter we store in as some other member variable? Or something else?

[tamuri]

Yes, we read the dataframe, pass it to consumables and then it will fall out of scope when the method ends and be cleaned up. Once consumables are set up, I don't think it's needed. Of course, if it's needed for some other lookup we'll need to keep it.