Fix viewability callbacks after data updates

[OskarEichler]

Description

When the data reference changed but the visible indices stayed the same, the viewability helper retained its index cache and suppressed onViewableItemsChanged. Consumers therefore continued to hold tokens for the previous items until scrolling changed visibility.

Reset the existing viewability cache in the data-update path so the post-commit visibility calculation reports the replacement items. This matches React Native VirtualizedList behavior while leaving normal scroll calculations unchanged.

Reviewers’ hat-rack 🎩

• Replace visible keyed data without scrolling and verify the callback receives the new item.
• Confirm ordinary scrolling still avoids duplicate callbacks.

Verification

• jest --runInBand — 188 tests passed
• eslint . --ext .ts,.tsx
• tsc --pretty --noEmit
• react-doctor . --verbose --diff — 100/100
• git diff --check

Screenshots or videos (if needed)

Not applicable.