Allowlist yoga dimension/position/flex props for native animated backend

[Copilot]

Port of facebook/react-native#56375. Adds yoga layout properties to the native animation allowlist behind the useSharedAnimatedBackend feature flag.

Changes

• NativeAnimatedAllowlist.js: Conditionally spread dimension (height, width, min*, max*), position (top, bottom, left, right, start, end), and flex props into SUPPORTED_STYLES when useSharedAnimatedBackend() is enabled
• Supporting stubs: Minimal ReactNativeFeatureFlags.js and AnimatedProps.js type definitions to satisfy imports

// New allowlisted props, gated behind feature flag
...(ReactNativeFeatureFlags.useSharedAnimatedBackend()
  ? {
      height: true, maxHeight: true, maxWidth: true,
      minHeight: true, minWidth: true, width: true,
      bottom: true, end: true, left: true,
      right: true, start: true, top: true,
      flex: true,
    }
  : {}),