[Uptime] [Synthetics] Undesired layout shift when expanding field on journey summary page

[justinkambic]

Kibana version:

latest

Elasticsearch version:

latest

Server OS version:

macOS

Browser version:

Chrome 96+

Browser OS version:

macOS

Original install method (e.g. download page, yum, from source, etc.):

from source

Describe the bug:

Layout shift happens because the scrollbar is exposed when the script field is expanded/contracted.

Steps to reproduce:

1. Create a synthetic monitor
2. Navigate to a journey's summary page
3. Expand a step and view the script

Expected behavior:

The layout shouldn't have any lateral shift

Screenshots (if relevant):

Errors in browser console (if relevant):

Provide logs and/or server output (if relevant):

Any additional context:

[elasticmachine]

Pinging @elastic/uptime (Team:uptime)