[8.x] [ResponseOps] Document creating task-manager serverless monitoring assets - adding to kibana dev docs navigation (#210902) (#210929)

# Backport

This will backport the following commits from `main` to `8.x`:
- [[ResponseOps] Document creating task-manager serverless monitoring
assets - adding to kibana dev docs navigation
(#210902)](https://github.com/elastic/kibana/pull/210902)

<!--- Backport version: 9.4.3 -->

### Questions ?
Please refer to the [Backport tool
documentation](https://github.com/sqren/backport)

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Co-authored-by: Alexi Doak <109488926+doakalexi@users.noreply.github.com>

dev_docs/nav-kibana-dev.docnav.json

@@ -229,6 +229,9 @@
         },
         {
           "id": "kibDevTutorialsSolutionNavigation"
+        },
+        {
+          "id": "kbServerlessTaskManagerMonitoring"
         }
       ]
     },