fix(iOS): classify CFNetwork as a system framework in the header include-health ratchet

The compose-xcframework job's "Verify composed headers" step failed the
include-health ratchet with two NEW unresolvable includes:

  unresolved CoreModules/RCTInspectorWebSocketReporter.h -> CFNetwork/CFNetwork.h
  unresolved React/RCTInspectorWebSocketReporter.h -> CFNetwork/CFNetwork.h

RCTInspectorWebSocketReporter.h (#57543) imports <CFNetwork/CFNetwork.h>
for CFHTTPMessageRef. CFNetwork is a real Apple system framework, always
available in the SDK, but it was missing from the SDK_PREFIXES allowlist
in headers-inventory.js, so the ratchet classified the include as
unresolvable. Adding it alongside CoreFoundation/Security/Network fixes
the classification; no baseline change is needed.

Author: cipolleschi

packages/react-native/scripts/ios-prebuild/headers-inventory.js

@@ -86,6 +86,7 @@ const SDK_PREFIXES = new Set([
   'Accessibility',
   'AVFoundation',
   'AVKit',
+  'CFNetwork',
   'CommonCrypto',
   'CoreFoundation',
   'CoreGraphics',