[CI] Stop Xcode 14, start Xcode 15.3 #2321

Job	Run time
catalyst	2m 13s
pod-lib-lint (ios, macos-14)	4m 9s
pod-lib-lint (ios, macos-13)	7m 19s
quickstart	25m 46s
pod-lib-lint (tvos, macos-14)	2m 14s
pod-lib-lint (tvos, macos-13)	3m 59s
quickstart-ftl-cron-only	0s
pod-lib-lint (macos --skip-tests, macos-14)	1m 41s
pod-lib-lint (macos --skip-tests, macos-13)	2m 54s
spm (iOS, macos-13)	6m 6s
pod-lib-lint (watchos, macos-14)	1m 21s
spm (iOS, macos-14)	5m 38s
pod-lib-lint (watchos, macos-13)	2m 52s
spm (tvOS, macos-13)	2m 52s
spm (tvOS, macos-14)	1m 54s
spm (macOS, macos-13)	3m 2s
spm (macOS, macos-14)	1m 30s
spm (catalyst, macos-13)	2m 26s
spm (catalyst, macos-14)	1m 29s
spm (watchOS, macos-13)	4m 11s
spm (watchOS, macos-14)	2m 39s
spm (macos-14, visionOS, Xcode_15.2)	1m 58s
abtesting-cron-only	0s
	1h 28m 13s

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