[CI/Build] Add opentelemetry libs in default vllm build (requirements/common.txt) (#34466)

Signed-off-by: Vlad Mihailescu <vtmihailescu@gmail.com>

examples/online_serving/opentelemetry/README.md

 # Setup OpenTelemetry POC
 
-1. Install OpenTelemetry packages:
-
-    ```bash
-    pip install \
-      'opentelemetry-sdk>=1.26.0,<1.27.0' \
-      'opentelemetry-api>=1.26.0,<1.27.0' \
-      'opentelemetry-exporter-otlp>=1.26.0,<1.27.0' \
-      'opentelemetry-semantic-conventions-ai>=0.4.1,<0.5.0'
-    ```
+> **Note:** The core OpenTelemetry packages (`opentelemetry-sdk`, `opentelemetry-api`, `opentelemetry-exporter-otlp`, `opentelemetry-semantic-conventions-ai`) are bundled with vLLM. Manual installation is not required.
 
 1. Start Jaeger in a docker container:
 

requirements/common.txt

@@ -53,3 +53,7 @@ model-hosting-container-standards >= 0.1.13, < 1.0.0
 mcp
 grpcio
 grpcio-reflection
+opentelemetry-sdk >= 1.27.0
+opentelemetry-api >= 1.27.0
+opentelemetry-exporter-otlp >= 1.27.0
+opentelemetry-semantic-conventions-ai >= 0.4.1