[Scheduler] 视频理解支持chunk prefill

[yangjianfengo1]

Motivation

对于长视频来说token太多，所占激活显存太多，故推理时支持chunk prefill，并且视频的chunk prefill只能帧与帧切割

Modifications

修改了多模中的视频理解每次推理时给引擎的token数

Usage or Command

请求中带入can_split_idx字段就好，这个数组中的每个值是可以切割的下标，例如token_num=10，can_split_list=[2,5,9]，表述chunk fill时可以分3次推理，每次的token数分别是[3,3,4]

Accuracy Tests

模型单测通过

Checklist

• Add at least a tag in the PR title.
  • Tag list: [[FDConfig],[APIServer],[Engine], [Scheduler], [PD Disaggregation], [Executor], [Graph Optimization], [Speculative Decoding], [RL], [Models], [Quantization], [Loader], [OP], [KVCache], [DataProcessor], [BugFix], [Docs], [CI], [Optimization], [Feature], [Benchmark], [Others], [XPU], [HPU], [GCU], [DCU], [Iluvatar], [Metax]]
  • You can add new tags based on the PR content, but the semantics must be clear.
• Format your code, run pre-commit before commit.
• Add unit tests. Please write the reason in this PR if no unit tests.
• Provide accuracy results.
• If the current PR is submitting to the release branch, make sure the PR has been submitted to the develop branch, then cherry-pick it to the release branch with the [Cherry-Pick] PR tag.

[paddle-bot]

Thanks for your contribution!