Bump ray from 2.46.0 to 2.55.0 in /single-turn

Bumps [ray](https://github.com/ray-project/ray) from 2.46.0 to 2.55.0.
- [Release notes](https://github.com/ray-project/ray/releases)
- [Commits](ray-project/ray@ray-2.46.0...ray-2.55.0)

---
updated-dependencies:
- dependency-name: ray
  dependency-version: 2.55.0
  dependency-type: direct:production
...

Signed-off-by: dependabot[bot] <support@github.com>

Author: dependabot[bot]

single-turn/requirements-npu.txt

@@ -12,7 +12,7 @@ pybind11
 pylatexenc
 tensordict>=0.8.0,<=0.10.0,!=0.9.0
 transformers==4.52.4
-ray==2.46.0
+ray==2.55.0
 wandb
 mathruler
 torchdata

single-turn/requirements_sglang.txt

@@ -11,7 +11,7 @@ peft
 pyarrow>=19.0.0
 pybind11
 pylatexenc
-ray[default]>=2.10
+ray[default]>=2.55.0
 tensordict>=0.8.0,<=0.10.0,!=0.9.0
 torchdata
 torchvision