fix(ios): remove safe area release warnings

[huytdps13400]

Summary

Fixes #739.

• initialize the generated inset event in its C++ declaration order (top, right, bottom, left), removing the two -Wreorder-init-list diagnostics emitted per simulator architecture
• move RNCSafeAreaViewState's default constructor out of the header, so RNCSafeAreaViewState.cpp always emits a real external symbol when the Android-only implementation is compiled out on Apple platforms

This keeps the constructor behavior unchanged and avoids adding a dummy symbol solely to satisfy libtool.

Test Plan

• Baseline Fabric Release build on Xcode 26.5 reproduced both reorder warnings and libtool: warning: 'RNCSafeAreaViewState.o' has no symbols.

• Repeated the same build after the patch:

  xcodebuild -quiet \
    -scheme ReactTestApp \
    -workspace RNSACExample.xcworkspace \
    -destination 'generic/platform=iOS Simulator' \
    ONLY_ACTIVE_ARCH=NO \
    -configuration Release \
    CODE_SIGNING_ALLOWED=NO

  The build succeeds without either safe-area-context warning. Remaining warnings are from React Native/generated third-party pods.

• nm -gU on both arm64 and x86_64 Release objects reports the external RNCSafeAreaViewState constructor symbols.

• ./.github/scripts/build-android.sh true — Fabric debug build succeeds for arm64-v8a, armeabi-v7a, x86, and x86_64.

• ./.github/scripts/build-android.sh false — succeeds; React Native 0.85 reports that New Architecture can no longer be disabled.

• yarn format:prettier:check

• yarn format:clang:check

• yarn validate:eslint — zero errors; three existing deep-import warnings

• yarn validate:typescript

• yarn validate:jest — 21/21 tests, 11/11 snapshots

• yarn prepare — CommonJS, ESM, and TypeScript declaration builds

yarn test was also attempted, but its unchanged Android spotlessCheck subtask stalled at spotlessGroovyGradle for over five minutes on local Gradle 9.4.1. All other test-script subcommands above were run independently; no Android/Gradle source is changed in this PR.