All nightly moonlight tests failing with sentencepiece error

**Describe the bug**
All nightly moonlight tests failing with error despite sentenepiece being in direct rl dependencies:

```
ValueError: Couldn't instantiate the backend tokenizer from one of:
(1) a `tokenizers` library serialization file,
(2) a slow tokenizer instance to convert or
(3) an equivalent slow tokenizer class to instantiate and convert.
You need to have sentencepiece or tiktoken installed to convert a slow tokenizer to a fast one.

```
**Steps/Code to reproduce bug**

Tests failing off main branch:
llm_grpo_moonlight_16ba3b_4n8g_megatron_fp8_e2e
llm_grpo_moonlight_16ba3b_4n8g_megatron
llm_grpo_moonlight_16ba3b_4n8g_megatron_tq_simple etc.

**Additional context**

Failures after PR https://github.com/NVIDIA-NeMo/RL/pull/2489 merged