Allow Customization of Cursor Color in Native PaymentSheet (`initPaymentSheet`)

[guiroco]

Description:

I'm using the flutter_stripe package and relying on initPaymentSheet to present the native Payment Sheet UI. While the current theming options (such as colors, shapes, and fonts) are helpful, I noticed that it's not possible to customize the cursor color inside the Payment Sheet’s input fields (e.g., card number, expiry).

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Why This Matters

In apps with custom themes (e.g., light text on dark background, or brand-specific colors), the default cursor color may clash with the app's styling or hinder accessibility. Supporting cursor color customization would improve UI consistency and user experience.

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Suggested API Design

It would be ideal to expose a parameter in PaymentSheetAppearance, for example:

cursorColor: Color

[remonh87]

we need to wait for: stripe/stripe-android#8021 to be fixed here