fix(ci): preserve STT e2e provider JSON (#5287)

Forward detected provider output with printf so workflow matrices receive valid JSON.

Author: ComputelessComputer

.github/workflows/stt_e2e.yaml

@@ -87,7 +87,7 @@ jobs:
           if [ "${{ github.event_name }}" == "workflow_dispatch" ]; then
             echo 'providers=["${{ inputs.provider }}"]' >> $GITHUB_OUTPUT
           else
-            echo "providers=${{ needs.detect-changes.outputs.providers }}" >> $GITHUB_OUTPUT
+            printf 'providers=%s\n' '${{ needs.detect-changes.outputs.providers }}' >> "$GITHUB_OUTPUT"
           fi
 
   direct-provider-batch-e2e: