Update to Xcode 15.2 in CI workflows #2208

Job	Run time
catalyst	3m 30s
quickstart	14m 48s
pod-lib-lint (ios, macos-12)	8m 50s
quickstart-ftl-cron-only	0s
pod-lib-lint (ios, macos-13)	9m 34s
pod-lib-lint (tvos, macos-12)	3m 54s
spm (iOS, macos-12)	4m 13s
pod-lib-lint (tvos, macos-13)	4m 59s
spm (iOS, macos-13)	5m 27s
pod-lib-lint (macos --skip-tests, macos-12)	4m 4s
spm (tvOS, macos-12)	4m 24s
pod-lib-lint (macos --skip-tests, macos-13)	3m 6s
spm (tvOS, macos-13)	4m 1s
pod-lib-lint (watchos, macos-12)	2m 7s
spm (macOS, macos-12)	2m 16s
pod-lib-lint (watchos, macos-13)	2m 50s
spm (macOS, macos-13)	2m 25s
spm (catalyst, macos-12)	2m 29s
spm (catalyst, macos-13)	2m 57s
spm (watchOS, macos-12)	4m 2s
spm (watchOS, macos-13)	4m 14s
abtesting-cron-only	0s
	1h 34m 10s

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