Is your feature request related to a problem? Please describe.
I'm currently integrating the in a React Native app. One common UX expectation is to provide user feedback (like a loading spinner) while the payment flow is initiating or in progress.

Right now, there's no built-in support for a loading indicator or loader prop on the button, which results in either:
The user tapping multiple times
Manual handling outside the component

Describe the solution you'd like
It would be great if the component accepted a loader prop (boolean or custom component), allowing developers to:
Show a spinner or progress indicator on top of the button
Customize the loader style if needed

<GooglePayButton
loading={isProcessing}
loader={}
/>

Describe alternatives you've considered
A clear and concise description of any alternative solutions or features you've considered.
Wrapping in a parent View and overlaying a loader manually
Additional context
Add any other context or screenshots about the feature request here.