[BugFix] fix cache manager not launched in case of mtp or blockwise fp8

[liyonghua0910]

Motivation

• 修复开启 MTP 时 cache manager 启动失败的问题
• 修复 blockwise fp8 精度部署时 cache manager 启动失败的问题

Modifications

• 为 mtp 和 block_wise_fp8 补充 set_data_ipc 调用
• 调换 mtp 模型和主模型的 cache 初始化顺序（因为主模型和 mtp 模型的 cache 是分别创建，而主模型的 cache 创建完毕就会通知 cache transfer 进程读取，需要在此时确保所有层 cache 已就绪）

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.

[codecov-commenter]

Codecov Report

❌ Patch coverage is 37.50000% with 5 lines in your changes missing coverage. Please review.
⚠️ Please upload report for BASE (develop@b03a4f3). Learn more about missing BASE report.

Files with missing lines	Patch %	Lines
fastdeploy/spec_decode/mtp.py	50.00%	3 Missing ⚠️
fastdeploy/worker/gpu_model_runner.py	0.00%	2 Missing ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##             develop    #5840   +/-   ##
==========================================
  Coverage           ?   66.78%           
==========================================
  Files              ?      347           
  Lines              ?    44371           
  Branches           ?     6816           
==========================================
  Hits               ?    29632           
  Misses             ?    12556           
  Partials           ?     2183           

Flag	Coverage Δ
GPU	66.78% <37.50%> (?)

Flags with carried forward coverage won't be shown. Click here to find out more.

☔ View full report in Codecov by Sentry.
📢 Have feedback on the report? Share it here.

🚀 New features to boost your workflow:

• ❄️ Test Analytics: Detect flaky tests, report on failures, and find test suite problems.