Generate initialHidden as an optional prop for VirtualView (#58864)

[bartlomiejbloniarz]

Summary:

VirtualViewNativeComponent declared initialHidden?: boolean, which codegen generated as a plain bool defaulting to false. On Android, props equal to their C++ default are not sent when a view is created, so an explicit initialHidden={false} never reached ReactVirtualViewManager.setInitialHidden. The view's mode stayed null, so it emitted a synchronous Visible mode change on its first update, emitted a normally suppressed Prerender change, and skipped the clipping update when it first left Visible.

Declare the prop as WithDefault<boolean, null> and opt the spec into generateOptionalProperties, so initialHidden is a std::optional<bool> that is unset by default and an explicit false is sent. A plain ?: boolean is not enough, because the Flow parser assigns it a false default. The codegenNativeComponent Flow options type gains the codegen options already declared in its TypeScript types, and iOS reads the prop with value_or(false).

This changes generated APIs of VirtualView: VirtualViewProps::initialHidden becomes std::optional<bool>, and VirtualViewManagerInterface.setInitialHidden takes a nullable Boolean. The public JS API change is additive: NativeComponentOptions gains the optional generateOptionalProperties and generateOptionalObjectProperties fields, so the API snapshot reports codegenNativeComponent as changed without breaking existing callers.

Changelog: [General][Fixed] - Fix VirtualView initial mode when initialHidden is not sent on creation

Reviewed By: javache

Differential Revision: D123029234

[meta-codesync]

@bartlomiejbloniarz has exported this pull request. If you are a Meta employee, you can view the originating Diff in D123029234.

[github-actions]

Warning

JavaScript API change detected

This PR commits an update to ReactNativeApi.d.ts, indicating a change to React Native's public JavaScript API.

• Please include a clear changelog message.
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This change was flagged as: POTENTIALLY_BREAKING