[CI] move cancel_previous_workflows to ubuntu-latest

[KuilongCui]

Previously, cancel_previous_workflows ran on self-hosted runners, but all workflows were executed in a queued manner on the self-hosted environment, which prevented cancel_previous_workflows from canceling workflows submitted on the current branch. Changing it to ubuntu-latest can resolve this issue.

[github-actions]

migration_size	8.00 MB	16.00 MB	24.00 MB	32.00 MB	40.00 MB	48.00 MB	56.00 MB	64.00 MB	72.00 MB	80.00 MB	88.00 MB	96.00 MB	104.00 MB	112.00 MB	120.00 MB	128.00 MB	136.00 MB	144.00 MB	152.00 MB	160.00 MB	176.00 MB	280.00 MB	312.00 MB	480.00 MB	536.00 MB	560.00 MB	568.00 MB	576.00 MB	584.00 MB	688.00 MB	696.00 MB
rpc_speed(GB/s)	1.04	1.53	1.76	1.91	1.97	2.01	2.06	2.05	2.11	2.27	2.30	2.29	2.35	2.19	2.20	2.40	2.38	2.49	2.42	2.42	2.39	2.44	2.56	3.09	3.05	2.99	3.07	3.19	2.98	3.16	3.18

migration_size	8.00 MB	16.00 MB	24.00 MB	32.00 MB	40.00 MB	48.00 MB	56.00 MB	64.00 MB	72.00 MB	80.00 MB	88.00 MB	96.00 MB	104.00 MB	112.00 MB	120.00 MB	128.00 MB	136.00 MB	152.00 MB	160.00 MB	168.00 MB	176.00 MB	192.00 MB	312.00 MB	472.00 MB	480.00 MB	560.00 MB	568.00 MB	576.00 MB	688.00 MB
gloo_speed(GB/s)	0.94	1.58	1.99	2.26	2.29	2.54	2.71	2.71	2.64	2.82	3.04	2.18	2.89	2.55	2.87	2.49	2.87	2.73	2.60	2.83	2.72	2.36	2.16	2.09	2.64	2.82	2.75	2.75	2.30

migration_size	8.00 MB	16.00 MB	24.00 MB	32.00 MB	40.00 MB	48.00 MB	56.00 MB	64.00 MB	72.00 MB	80.00 MB	88.00 MB	96.00 MB	104.00 MB	112.00 MB	120.00 MB	128.00 MB	136.00 MB	144.00 MB	152.00 MB	160.00 MB	176.00 MB	280.00 MB	288.00 MB	312.00 MB	480.00 MB	536.00 MB	560.00 MB	568.00 MB	696.00 MB
nccl_speed(GB/s)	0.19	0.51	0.71	0.84	1.02	1.32	1.38	1.53	1.67	1.80	1.94	2.00	2.28	2.47	2.30	2.68	1.53	3.33	2.72	3.01	4.38	2.91	2.67	4.29	5.34	4.43	4.34	3.70	4.31

[github-actions]

prefill	p25	p50	p75	p95	p99	mean
latency(ms)	35338.00	107428.50	181690.50	253502.40	256459.02	114835.36

decode	p25	p50	p75	p95	p99	mean
latency(ms)	53.04	60.41	76.05	127.82	341.55	77.77