[8.6] [Security Solution] [Platform] Adds 'Optional' to the default d…

…escription message when editing (#146108) (#146217)

# Backport

This will backport the following commits from `main` to `8.6`:
- [[Security Solution] [Platform] Adds 'Optional' to the default
description message when editing
(#146108)](#146108)

<!--- Backport version: 8.9.7 -->

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

<!--BACKPORT [{"author":{"name":"Gloria
Hornero","email":"gloria.hornero@elastic.co"},"sourceCommit":{"committedDate":"2022-11-23T19:31:56Z","message":"[Security
Solution] [Platform] Adds 'Optional' to the default description message
when editing
(#146108)","sha":"efe6967a4ccdc0beed1db648aebf866199ef78f9","branchLabelMapping":{"^v8.7.0$":"main","^v(\\d+).(\\d+).\\d+$":"$1.$2"}},"sourcePullRequest":{"labels":["release_note:skip","Team:Detections
and Resp","Team: SecuritySolution","Team:Security Solution
Platform","v8.6.0","v8.7.0"],"number":146108,"url":"https://github.com/elastic/kibana/pull/146108","mergeCommit":{"message":"[Security
Solution] [Platform] Adds 'Optional' to the default description message
when editing
(#146108)","sha":"efe6967a4ccdc0beed1db648aebf866199ef78f9"}},"sourceBranch":"main","suggestedTargetBranches":[],"targetPullRequestStates":[{"branch":"8.6","label":"v8.6.0","labelRegex":"^v(\\d+).(\\d+).\\d+$","isSourceBranch":false,"url":"https://github.com/elastic/kibana/pull/146216","number":146216,"state":"OPEN"},{"branch":"main","label":"v8.7.0","labelRegex":"^v8.7.0$","isSourceBranch":true,"state":"MERGED","url":"https://github.com/elastic/kibana/pull/146108","number":146108,"mergeCommit":{"message":"[Security
Solution] [Platform] Adds 'Optional' to the default description message
when editing
(#146108)","sha":"efe6967a4ccdc0beed1db648aebf866199ef78f9"}}]}]
BACKPORT-->

Co-authored-by: Gloria Hornero <gloria.hornero@elastic.co>