Remove "experimental" banner for OTel Metrics (#40286)

(cherry picked from commit d5c1fc2)

Author: ferruzzi

airflow/www/templates/airflow/dags.html

@@ -119,9 +119,9 @@
       <a href={{ get_docs_url("executor/index.html") }}  target="_blank" rel="noopener noreferrer"><b>Click here</b></a> for more information.
     {% endcall %}
   {% endif %}
-  {% if otel_on | default(false) %}
+  {% if otel_traces_on | default(false) %}
     {% call show_message(category='warning', dismissible=false) %}
-      OpenTelemetry support is experimental. <a href="https://github.com/apache/airflow/blob/main/dev/breeze/doc/03_developer_tasks.rst#running-breeze-with-an-opentelemetry-metrics-stack" target="_blank" rel="noopener noreferrer">
+      OpenTelemetry tracing support is experimental. <a href="https://github.com/apache/airflow/blob/main/dev/breeze/doc/03_developer_tasks.rst#running-breeze-with-an-opentelemetry-stack" target="_blank" rel="noopener noreferrer">
         <b>Click here</b></a> for more information.
     {% endcall %}
   {% endif %}

newsfragments/40286.significant.rst

@@ -0,0 +1 @@
+Support for OpenTelemetry Metrics is no longer "Experimental"