CardField crashes the app when it's focused and unmounted while using the new architecture (Fabric)

[aganov]

Using the new NEW_ARCH (Fabric), the app crashes with the error: Swift runtime failure: force unwrapped a nil value + 0 [inlined] closure #1 in CardFieldManager.blur(_:) + 484 when the component containing CardField is unmounted while the CardField is focused.

To Reproduce
Steps to reproduce the behavior:

1. Create a screen with a CardField component and compile the iOS app with RCT_NEW_ARCH_ENABLED=1.
2. Focus on the CardField.
3. Unmount the screen (e.g., using navigation.goBack, bottomsheet.close, etc.).
4. See the crash.

Expected behavior
The app should dismiss keyboard and unmount the screen without crashing, even when the CardField is focused.

Screenshots
N/A

Desktop (please complete the following information):

• OS: iOS
• Browser: N/A
• Version: N/A

Smartphone (please complete the following information):

• Device: iPhone15
• OS: iOS 18.5
• Browser: N/A
• Version: N/A

Additional context
This issue occurs only when using the new Fabric architecture with RCT_NEW_ARCH_ENABLED=1. I have not tested on Android yet, the issue may also be present there.

[griffinshuth]

Android does not even show the CardField with Fabric enabled. This is a huge issue since react native 76 which is coming out next month will have the new Architecture enabled by default which will make this library unusable at that point. @charliecruzan-stripe any update on supporting Fabric?