ci: exclude vllm_inference and megatron from nightly recipe CI (#1554)

## Problem

- **vllm_inference** fails nightly because vLLM 0.15.1 requires
transformers<5 but the 26.03 container ships transformers 5.x, and vLLM
0.19.1 needs torch APIs not yet in the NGC build
- **megatron recipes** (eden_megatron, evo2_megatron) run as duplicates
— they already have their own dedicated workflow
(`unit-tests-mbridge-recipes.yaml`)

Both were already excluded from the `changed-files` filter (PR runs),
but scheduled (nightly) runs enumerate `ALL_DIRS` and bypass that
filter.

## Fix

Add `grep -v -E "vllm_inference|megatron"` to the `ALL_DIRS` computation
so both are excluded from nightly runs.

## Failing CI run
https://github.com/NVIDIA/bionemo-framework/actions/runs/24601629903

Signed-off-by: svc-bionemo <267129667+svc-bionemo@users.noreply.github.com>
Co-authored-by: svc-bionemo <267129667+svc-bionemo@users.noreply.github.com>

Author: svc-bionemo

.github/workflows/unit-tests-recipes.yml

@@ -66,7 +66,7 @@ jobs:
           CHANGED_FILES: ${{ steps.changed-files.outputs.all_changed_files }}
         run: |
           # Get all recipe and model directories
-          ALL_DIRS=$(ls -d bionemo-recipes/models/*/ bionemo-recipes/recipes/*/ 2>/dev/null | jq -R -s -c 'split("\n")[:-1] | map(rtrimstr("/"))')
+          ALL_DIRS=$(ls -d bionemo-recipes/models/*/ bionemo-recipes/recipes/*/ 2>/dev/null | grep -v -E "vllm_inference|megatron" | jq -R -s -c 'split("\n")[:-1] | map(rtrimstr("/"))')
 
           # Helper to check for a PR label
           has_label() {