feat(chat): update for Mynah UI to beta 6 (aws#7104)

## Problem
New updates for mynah UI from beta-6

## Solution
- update for Mynah UI to beta 6

---

- Treat all work as PUBLIC. Private `feature/x` branches will not be
squash-merged at release time.
- Your code changes must meet the guidelines in
[CONTRIBUTING.md](https://github.com/aws/aws-toolkit-vscode/blob/master/CONTRIBUTING.md#guidelines).
- License: I confirm that my contribution is made under the terms of the
Apache 2.0 license.

Author: ashishrp-aws

package-lock.json

@@ -525,7 +525,7 @@
         "@aws-sdk/s3-request-presigner": "<3.731.0",
         "@aws-sdk/smithy-client": "<3.731.0",
         "@aws-sdk/util-arn-parser": "<3.731.0",
-        "@aws/mynah-ui": "^4.31.0-beta.5",
+        "@aws/mynah-ui": "^4.31.0-beta.6",
         "@gerhobbelt/gitignore-parser": "^0.2.0-9",
         "@iarna/toml": "^2.2.5",
         "@smithy/fetch-http-handler": "^5.0.1",