Temporarily return ios-fieldtrial-rel to targeting Mac-13|Mac-14 until bots upgrade

Bug: 345748239
Change-Id: Ib336a58a1ba9ee9e1a89a773392401976795fde9
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/5605637


Reviewed-by: Yue She <yueshe@google.com>
Commit-Queue: Will Yeager <wyeager@google.com>
Reviewed-by: Zhaoyang Li <zhaoyangli@chromium.org>
Cr-Commit-Position: refs/heads/main@{#1312203}