[infra][iOS][tvOS] Update Apple mobile OS versions used for CI testing to 18.x

[matouskozak]

To keep up with the evolving Apple ecosystem and strict update policy we should update the testing infrastructure to the most current OS used by customers.

Currently, we are running tests on macOS 13.6.3, XCode 14.3, iOS 16.5 (or tvOS 16.3) on osx.13.amd64.iphone.open and osx.13.amd64.appletv.open queues.

We should update these queues to:

• macOS 15.x
• XCode 16.x
• iOS/tvOS 18.x

To ensure smooth transition, we have scouting queues (osx.amd64.iphone.scouting.open, osx.amd64.appletv.scouting.open) which can be updated to the desired configuration and used for testing purposes before the full migration.

After the verification on scouting queues is done, we should reach out to the Helix team to align on the update schedule for the osx.13.amd64.iphone.open and osx.13.amd64.appletv.open queues.

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Note

The same queues (osx.13.amd64.iphone.open and osx.13.amd64.appletv.open) are used for servicing branches. Consequently, any changes to these queues must be validated to be compatible with servicing CI infrastructure.

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