[DYNAMO] pass renderer transport to verifiers

[AmeenP]

Summary

Passes renderer_transport="dynamo" to verifiers renderer clients when client.backend = "dynamo", while preserving vllm for the default vLLM path.

Preserves backend when ElasticInferencePool rebuilds URL-scoped client configs, so elastic Dynamo renderer clients keep the same transport selection.

Updates the shared Dynamo renderer stack contract:

• pins verifiers to 9485194f (Add Dynamo renderer transport verifiers#1287)
• pins renderers to 17005dd ([DYNAMO] add chat nvext transport renderers#11)
• stops forcing return_token_ids in orchestrator env sampling defaults; token IDs are requested by the renderer/verifiers transport (nvext.engine_data for Dynamo)
• adds config coverage that return_token_ids is not injected globally

Stacked on #2398.

Companion PRs:

• verifiers: Add Dynamo renderer transport verifiers#1287
• renderers: [DYNAMO] add chat nvext transport renderers#11

Validation

Local:

• uv lock --check
• uvx ruff==0.13.0 check --config=pyproject.toml src/prime_rl/utils/client.py tests/unit/utils/test_client.py
• uvx ruff==0.13.0 format --check --config=pyproject.toml src/prime_rl/utils/client.py tests/unit/utils/test_client.py

GitHub Actions:

• Ruff: pass
• Slim install (prime-rl-configs only): pass
• Unit tests: pass

Local test note:

• uv run pytest tests/unit/utils/test_client.py is blocked on macOS by the repo's Linux-only lockfile; uv run --no-sync pytest tests/unit/utils/test_client.py exited 139 locally.