[DOC] Add deprecation for metrics summary (#4193)

* Add deprecation for metrics summary

* Update docs/sources/tempo/api_docs/metrics-summary.md

* Update docs/sources/tempo/api_docs/metrics-summary.md

* Apply suggestions from code review

Co-authored-by: Jennifer Villa <jvilla2013@gmail.com>

---------

Co-authored-by: Jennifer Villa <jvilla2013@gmail.com>

docs/sources/tempo/api_docs/metrics-summary.md

@@ -10,17 +10,18 @@ weight: 600
 # Metrics summary API
 
 {{< admonition type="warning" >}}
-The Metrics summary API is an [experimental feature](/docs/release-life-cycle) that is disabled by default. To enable it, adjust your configuration as suggested below.
+The metrics summary API is deprecated as of Tempo 2.7. Features powered by the metrics summary API, like the Aggregate by table, are also deprecated in Grafana Cloud and Grafana 11.3 and later.
+It will be removed in a future release.
 {{% /admonition %}}
 
 This document explains how to use the metrics summary API in Tempo.
 This API returns RED metrics (span count, erroring span count, and latency information) for `kind=server` spans sent to Tempo in the last hour, grouped by a user-specified attribute.
 
 {{< youtube id="g97CjKOZqT4" >}}
 
-## Configuration
+## Activate metrics summary
 
-To enable the experimental metrics summary API, you must turn on the local blocks processor in the metrics generator.
+To enable the (deprecated) metrics summary API, you must turn on the local blocks processor in the metrics generator.
 Be aware that the generator uses considerably more resources, including disk space, if it's enabled:
 
 ```yaml
@@ -30,6 +31,9 @@ overrides:
       processors: [..., 'local-blocks']
 ```
 
+In Grafana and Grafana Cloud, the Metrics summary API is disabled by default.
+To enable it in Grafana Cloud, contact Grafana Support.
+
 ## Request
 
 To make a request to this API, use the following endpoint on the query-frontend: