build: update to TypeScript 5.9 beta #8243

Job	Run time
lint	1m 6s
build	1m 5s
e2e_windows (windows-2025, 22, npm, 1)	54s
e2e_windows (windows-2025, 22, esbuild, 0)	49s
e2e_windows (windows-2025, 22, npm, 4)	56s
e2e_windows (windows-2025, 22, npm, 0)	56s
e2e_windows (windows-2025, 22, npm, 5)	53s
e2e_windows (windows-2025, 22, npm, 2)	1m 9s
e2e_windows (windows-2025, 22, esbuild, 4)	1m 1s
e2e_windows (windows-2025, 22, esbuild, 1)	57s
e2e_windows (windows-2025, 22, esbuild, 2)	56s
e2e_windows (windows-2025, 22, esbuild, 3)	58s
e2e_windows (windows-2025, 22, npm, 3)	1m 4s
e2e_windows (windows-2025, 22, esbuild, 5)	57s
test	1s
Browser Compatibility Tests	1s
publish-snapshots	1s
e2e-package-managers	1s
e2e-snapshots	1s
e2e	1s
	13m 47s

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