[BugFix] Fix crash when receive a req with structed output in DP attention mode.

[hcyz33]

Motivation

Fix the issuse:
#3600

Modifications

1. set sampling_info_done in idle batch.
2. use attn_tp_cpu_group when enable dp attention

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[zhaochenyang20]

@FrankLeeeee I've run the CI. And wait for your approve.

[zhaochenyang20]

Please review it, thansk!

[FrankLeeeee]

LGTM.

[zhaochenyang20]

@hcyz33 Thanks. We will merge it after passing the CI.