rent tab: edit old_dwellings_in_housing_companies_price_index_type

[NC-jsAhonen]

Tasotarkistus type is now editable

[juho-kettunen-nc]

Good progress! I however want to address the naming: the type field is not for index type. I don't think there exists multiple types for the index that would be available for choosing.

I see that the correct interpretation is already in place in docstring of the enum's "In Finnish"-section, which says that the enum is for "Tasotarkistuksen tyyppi". The name of the property would probably then be periodic_rent_adjustment_type, and enum PeriodicRentAdjustmentType.

[juho-kettunen-nc]

But I know there is time pressure to show this to customer tomorrow, so I'll create a ticket about changing the name later this week (EDIT: on second thought, no hurry this week). This way we can get this merged and displayed tomorrow, as this does not affect what is shown in UI.