chore(ci): Fix ObjC testing with latest Xcode

[dpogue]

Platforms affected

iOS

Motivation and Context

Tests would fail to run in Xcode 15 due to not having a iPhone 8 simulator with the latest runtime, and CONFIGURATION_BUILD_DIR was causing errors about Cordova.framework not being found and sometimes warnings about stale files.

Description

• Move macOS CI to run on macOS 14 on Apple Silicon, using Xcode 15
• Set the tests to run with an iPhone 15 simulator
• Fix a warning about a missing cast to AppDelegate*
• Set -derivedDataPath rather than CONFIGURATION_BUILD_DIR so that Apple doesn't cache stale data about previous runs

Testing

Ran in GitHub CI and locally with latest Xcode 15

Checklist

• [x] I've run the tests to see all new and existing tests pass

[codecov-commenter]

Codecov Report

All modified and coverable lines are covered by tests :white_check_mark:

Project coverage is 78.50%. Comparing base (c97845a) to head (50fdd29).

Additional details and impacted files

```diff @@ Coverage Diff @@ ## master #1412 +/- ## ======================================= Coverage 78.50% 78.50% ======================================= Files 16 16 Lines 1814 1814 ======================================= Hits 1424 1424 Misses 390 390 ```

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