Stop using paperComponentName in React Native core component specs

[christophpurrer]

Summary:
paperComponentName is a codegenNativeComponent option that makes the generated
view config announce the old-architecture (Paper) RCT-prefixed ViewManager name
instead of the component's own name. We no longer support the old architecture, so
core components should announce their real Fabric names.

Removes the option from the five core specs where it is provably redundant:

Spec	Name in view config
ActivityIndicatorViewNativeComponent.js	RCTActivityIndicatorView -> ActivityIndicatorView
RCTModalHostViewNativeComponent.js	RCTModalHostView -> ModalHostView
PullToRefreshViewNativeComponent.js	RCTRefreshControl -> PullToRefreshView
RCTSafeAreaViewNativeComponent.js	RCTSafeAreaView -> SafeAreaView
SwitchNativeComponent.js	RCTSwitch -> Switch

Each new name already resolves natively, so this is a no-op at runtime:

• iOS Fabric — the plugin keys in RCTFabricComponentsPlugins.mm and the
  react_fabric_component_plugin_provider entries in BUCK are all unprefixed and
  match the spec names exactly. Previously the RCT prefix was simply stripped again
  by componentNameByReactViewName(), which exists only to undo this legacy prefixing.
• Android Fabric — mount items carry the C++ descriptor name, not the JS name
  (IntBufferBatchMountItem), so Android is unaffected. ModalHostView still maps via
  FabricNameComponentMapping, and SafeAreaView still resolves to
  ReactSafeAreaViewManager through the generic "RCT$className" fallback in
  ViewManagerRegistry. PullToRefreshView and Switch are Android-excluded.

Deliberately out of scope:

• The codegen option itself is retained. 24 Meta-internal specs outside
  react-native-github still pass paperComponentName (RCTMapNativeComponent.js,
  SliderNativeComponent.js, the AdsLWI previews, MagicIsland, ...), as do
  third-party OSS libraries. getOptions() does not validate keys, so removing support
  would silently resolve those components to an unregistered name instead of erroring.
• RCTInputAccessoryViewNativeComponent.js keeps the option, where it is
  load-bearing: the spec name is InputAccessory but the C++ ComponentName is
  InputAccessoryView, so dropping it would fall through to
  RCTUnimplementedViewComponentView. Aligning those needs a rename of the codegen'd
  InputAccessoryProps/InputAccessoryEventEmitter symbols in handwritten C++/ObjC.
• paperComponentNameDeprecated, which still has 6 internal users.
• Documentation. The paperComponentName section of the name_mapping.md docs is
  refreshed in a separate diff, so this one touches no Markdown.

Also updates the RCTSwitch fiber-type checks in ReactTreeSerializer.js to accept
Switch, mirroring the existing check in its sibling DebugInteractions.js.

Snapshot churn is the renamed element names only. The RCTRefreshControl entries in
the VirtualizedList/RelayPaginationView snapshots are unchanged because they come
from the hardcoded packages/jest-preset/jest/mocks/RefreshControl.js mock, not from
the view config.

Changelog:

[General][Changed] - Core components (ActivityIndicatorView, ModalHostView, PullToRefreshView, SafeAreaView, Switch) no longer report legacy RCT-prefixed names in their view configs

Differential Revision: D117877024

[meta-codesync]

@christophpurrer has exported this pull request. If you are a Meta employee, you can view the originating Diff in D117877024.