Docs: Update render service tracing (#106698)

Co-authored-by: jtvdez <jacob.valdez@grafana.com>

docs/sources/setup-grafana/image-rendering/_index.md

@@ -365,6 +365,30 @@ RENDERING_DUMPIO=true
 }
 ```
 
+#### Tracing
+
+{{< admonition type="note" >}}
+Tracing is supported in the image renderer v3.12.6 and later.
+{{< /admonition >}}
+
+Set the tracing URL to enable OpenTelemetry Tracing. The default is empty (disabled).
+You can also configure the service name that will be set in the traces. The default is `grafana-image-renderer`.
+
+```bash
+RENDERING_TRACING_URL="http://localhost:4318/v1/traces"
+```
+
+```json
+{
+  "rendering": {
+    "tracing": {
+      "url": "http://localhost:4318/v1/traces",
+      "serviceName": "grafana-renderer"
+    }
+  }
+}
+```
+
 #### Custom Chrome/Chromium
 
 If you already have [Chrome](https://www.google.com/chrome/) or [Chromium](https://www.chromium.org/)
@@ -580,21 +604,3 @@ RENDERING_VIEWPORT_PAGE_ZOOM_LEVEL=1
   }
 }
 ```
-
-#### Tracing
-
-Enable OpenTelemetry Tracing by setting the tracing URL. Default is empty (disabled).
-
-```bash
-RENDERING_TRACING_URL="http://localhost:4318/v1/traces"
-```
-
-```json
-{
-  "rendering": {
-    "tracing": {
-      "url": "http://localhost:4318/v1/traces"
-    }
-  }
-}
-```