Add type-test for View imperative handle methods

[sbalagan22]

Summary:

Calling imperative handle methods on a View ref works through React.ComponentRef<typeof View>, but the public type-tests only covered measure, measureInWindow, and setNativeProps, leaving measureLayout with no type-level regression guard. This adds a focused type-test that pins the full handle contract against both the legacy and the generated strict public types.

Root cause of the gap: a ref to a host component resolves to its imperative handle (ReactNativeElement under the strict types), not to the View component type. The component type is a function and does not carry the native methods, so the type that must be exercised is React.ComponentRef<typeof View>. Without a test asserting measureLayout on that type, a change to the handle surface could drop the method from the public types without failing CI.

Fix: add packages/react-native/__typetests__/view-ref.tsx asserting measure, measureInWindow, measureLayout, and setNativeProps on React.ComponentRef<typeof View>. The file lives in the shared __typetests__ directory, so it is type-checked against both types/ (legacy) and types_generated/ (strict, via react-native-strict-api).

On ViewInstance (per @huntie's note on #54104)

Checked how the new ViewInstance / per-component *Instance types affect this test. Findings from the repo:

• ViewInstance is exported today on main (packages/react-native/Libraries/Components/View/View.js: export type ViewInstance = HostInstance, re-exported from index.js.flow) and is present in 0.87-stable but not in 0.86-stable, so it ships in 0.87 as noted.
• It is part of the Strict TypeScript API only (introduced in Add *Instance type exports for all built-in components (#56953) #56953, aligned in Align to canonical *Instance types in component ref annotations (#56951) #56951, per RFC: Add dedicated Instance types for built-in component refs (JS API stabilization) react-native-community/discussions-and-proposals#1003). The legacy hand-written types/ still model View as class View extends ViewBase and do not export ViewInstance.
• ViewInstance resolves to HostInstance / ReactNativeElement, the same handle React.ComponentRef<typeof View> resolves to, so it covers all four methods this test pins. React.ComponentRef<typeof View> is not superseded for this purpose and is still used in __typetests__/index.tsx.

Because this test is checked against both the legacy and strict variants, it stays on React.ComponentRef<typeof View>: that is the spelling valid under both, whereas ViewInstance would not resolve under the legacy variant. Once the strict API is the default, a strict-only follow-up could assert the same contract through useRef<ViewInstance> directly.

Changelog:

[INTERNAL] [ADDED] - Add type-test for View imperative handle methods

Test Plan:

Both type-check suites pass with the new file, and the file lints clean.

$ yarn test-typescript
$ tsc -p packages/react-native/types/tsconfig.json
(exit 0)

$ yarn test-generated-typescript
$ tsc -p packages/react-native/types_generated/tsconfig.test.json
(exit 0)

$ eslint --max-warnings 0 packages/react-native/__typetests__/view-ref.tsx
(exit 0)

Confirmed the test guards the contract: adding a call to a non-existent method on the ref (view.nonExistentMethod123()) fails both suites with TS2339: Property 'nonExistentMethod123' does not exist on type 'ReactNativeElement' (strict) and ... on type 'View' (legacy). Removing that line restores a clean pass.

This does not change the behavior reported in #54104 that useRef<View>().measure() errors under the strict types; per @huntie that is addressed for app code in 0.87 via useRef<ViewInstance>. This PR guards the existing supported pattern and closes the measureLayout coverage gap.

Refs #54104

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[huntie]

nit: Can we rename this file component-refs.tsx?

[sbalagan22]

Done, renamed to component-refs.tsx.

[sbalagan22]

nit: Can we rename this file component-refs.tsx?

Thanks again for taking the time to review and merge this, it was a great first contribution to React Native for me. I'd really like to keep contributing here, so if there are areas that could use help or issues you'd point a newer contributor toward, I'd be glad to pick them up. Would love to stay in touch . https://www.linkedin.com/in/sukhmanbalagan/