Calling latestInvoice() on a subscription with no invoice results in a type error

[wsdimitri]

• Cashier Version: 12.11.0
• Laravel Version: 8.35.1
• PHP Version: 8.0.2

Description:

If you have a Stripe subscription with a null latest_invoice (ie. by creating the subscription with a back dated start date), calling latestInvoice() will throw a TypeError.

Laravel\Cashier\Invoice::__construct(): Argument #2 ($invoice) must be of type Stripe\Invoice, null given ...

I would think this should fail silently and return null?

Steps To Reproduce:

1. Create a Stripe subscription with a backdate_start_date.
2. Load the subscription into your Cashier Subscription model.
3. Call latestInvoice().

[driesvints]

Thanks. I've sent in a fix here: #1115