CP ci.yaml and configs to run on either macOS 13 or 14 for beta and stable

[vashworth]

Prerequisites

• Upgrade 50% of devicelab bots in each pool to macOS 14.5 #148881
• Upgrade 50% of chromium bots to macOS 14.5 #148891
• CP macOS 14 fixes for beta and stable #148886 - may want to wait for one release to be successful with those changes before doing this

---

CP the following:

• Update .ci.yaml in flutter/flutter to use either macOS 13 or macOS 14 #148871
• Update .ci.yaml and configs in flutter/engine to use either macOS 13 or macOS 14 #148879

[jmagman]

The engine and framework allow 13 or 14 on beta and stable.
Example on current stable branch:

flutter/.ci.yaml

Line 128 in 2663184

os: Mac-13|Mac-14

Closing.

[jmagman]

Hm, I guess this is tracking removing the spots we've pinned to macOS 13 like flutter/engine#53318. Reopening.