Refactor iOS device name detection to use OsType

This CL improves iOS device name simplification by refactoring the Apple
device detection logic to use the strongly-typed OsType enum

This refactoring especially ensures that non-Apple operating systems
running on Apple hardware are named consistently with their respective
OS conventions rather than being forced into Apple-specific templates.

Bug: 524738268
Change-Id: I83c06e501ec9ce665b7441ef95ffe3963cb998c5
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/7982971
Auto-Submit: Michael Tatarski <mtatarski@google.com>
Reviewed-by: Marc Treib <treib@chromium.org>
Commit-Queue: Michael Tatarski <mtatarski@google.com>
Cr-Commit-Position: refs/heads/main@{#1651079}