cherry-pick "Enhance Slow Store Scheduler" to `release-7.5-20251003-v7.5.6`

[okJiang]

Development Task

ref https://github.com/tikv/pd/issues/9359

[okJiang]

PD

• [x] https://github.com/tikv/pd/pull/9867
• [x] https://github.com/tikv/pd/pull/9871
• [x] https://github.com/tikv/pd/pull/9881
• [x] https://github.com/tikv/pd/pull/9906
  • [x] scheduler: implement network slow store scheduler
  • [x] slow-store: support changing config and add related test
  • [x] scheduler: slow score reaches 1, then wait for the recoveryGap before releasing the slow store
  • [x] scheduler: try to evict leader from network slow store
  • [x] test: add a test to check if network slow store is conflict with disk slow store

TiKV

• [x] https://github.com/tikv/tikv/pull/19067
• [x] https://github.com/tikv/tikv/pull/19035
• [x] https://github.com/tikv/tikv/pull/19053
• [x] https://github.com/tikv/tikv/pull/19090

Monitor

• [x] https://github.com/tikv/tikv/pull/19108
• [x] https://github.com/tikv/pd/pull/9941
• [x] https://github.com/tikv/tikv/pull/19116

[jebter]

Reference for the 8.5 branch: https://github.com/tikv/pd/issues/9962