[O11y][Cassandra] Migrate System Log dashboard visualizations to lens in kibana 8.3.0 (#5715)

* Migrate system log dashboard to lens

* Update changelog

Author: rajvi-patel-22

packages/cassandra/changelog.yml

@@ -1,4 +1,9 @@
 # newer versions go on top
+- version: "1.6.0"
+  changes:
+    - description: Migrate `System Logs` dashboard visualizations to lens.
+      type: enhancement
+      link: https://github.com/elastic/integrations/pull/5715
 - version: "1.5.0"
   changes:
     - description: Migrate `Overview` dashboard visualizations to lens.