Added missing entries in changelog (#4355)

## Changes
Added missing entries in changelog

## Why
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## Tests
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Author: andrewnester

NEXT_CHANGELOG.md

@@ -5,6 +5,7 @@
 ### Notable Changes
 
 ### CLI
+* Add support for Unified Host with experimental flag ([#4260](https://github.com/databricks/cli/pull/4260))
 
 ### Bundles