Make prefilled_customer properties optional

[ghost]

Hi! We're using your library and would like to use the prefilled_customer property when creating a redirectFlows (using client.redirectFlows.create).

We are using TypeScript and we can't use prefilled_customer without putting all the property with empty string for the one we don't want to fill.

For example if we omit region:

Property 'region' is missing in type '{ 
  address_line2: string; 
  address_line3: string; 
  ... 10 more ... ; 
  country_code: string; 
}'
but required in type 'RedirectFlowPrefilledCustomer'.

[tallosan]

Hey @RomainCscnLF, thanks for the report!

We'll be rolling out a fix for this in the next few days.