[Cherry-Pick][XPU][CI] lock xvllm version for fix bug(#7264)

[EmmonsCurse]

Cherry-pick of #7264 (authored by @plusNew001) to release/2.5.

devPR:#7264

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Motivation

💡 If this PR is a Cherry Pick, the PR title needs to follow the format by adding the [Cherry-Pick] label at the very beginning and appending the original PR ID at the end. For example, [Cherry-Pick][CI] Add check trigger and logic(#5191)

💡 如若此PR是Cherry Pick，PR标题需遵循格式，在最开始加上[Cherry-Pick]标签，以及最后面加上原PR ID，例如[Cherry-Pick][CI] Add check trigger and logic(#5191)

Modifications

Usage or Command

Accuracy Tests

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!

[fastdeploy-bot]

🤖 AI Code Review | 2026-04-09 12:48 CST

📋 Review 摘要

PR 概述：Cherry-pick #7264，将 XPU develop 分支的 xvllm 版本从 latest 锁定为固定版本 20260407，修复版本不稳定问题。

变更范围：custom_ops/xpu_ops/

影响面 Tag：[XPU] [CI]

📝 PR 规范检查

PR 描述未按模板填写 Motivation 和 Modifications 章节。建议补充变更原因和具体修改内容。

描述模板（可直接复制）：

## Motivation

锁定 develop 分支的 xvllm 版本，避免 `latest` 版本变化导致的 CI 不稳定问题。

## Modifications

- 将 `download_dependencies.sh` 中 develop 分支的 xvllm 版本从 `latest` 改为 `20260407`

问题

未发现阻塞性问题。

总体评价

变更内容清晰，将 develop 分支的 xvllm 版本从 latest 锁定为固定日期版本 20260407，是合理的 bug 修复策略。Cherry-pick 内容与原 PR #7264 一致，建议补充 PR 描述后合入。