ci: set `E2E_SHARD_TOTAL` as env variable #1841

Job	Run time
build	20s
lint	2m 18s
e2e_windows (windows-2025, 22, npm, 0)	48s
e2e_windows (windows-2025, 22, npm, 1)	39s
e2e_windows (windows-2025, 22, npm, 5)	24s
e2e_windows (windows-2025, 22, npm, 3)	29s
e2e_windows (windows-2025, 22, esbuild, 3)	24s
e2e_windows (windows-2025, 22, esbuild, 2)	32s
e2e_windows (windows-2025, 22, esbuild, 1)	28s
e2e_windows (windows-2025, 22, esbuild, 0)	26s
e2e_windows (windows-2025, 22, esbuild, 5)	31s
e2e_windows (windows-2025, 22, npm, 4)	34s
e2e_windows (windows-2025, 22, esbuild, 4)	32s
e2e_windows (windows-2025, 22, npm, 2)	27s
publish-snapshots	0s
test	0s
Browser Compatibility Tests	0s
e2e-package-managers	0s
e2e-snapshots	0s
e2e	0s
	8m 52s

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