Adding beta tag to opentelemetry support

Author: codyde

docs/platforms/javascript/common/opentelemetry/index.mdx

@@ -25,6 +25,7 @@ supported:
   - javascript.tanstackstart-react
 notSupported:
   - javascript
+beta: true
 ---
 
 The Sentry SDK uses [OpenTelemetry](https://opentelemetry.io/) under the hood. This means that any OpenTelemetry instrumentation that emits spans will automatically be picked up by Sentry without any further configuration.