[Security Solution] When adding a field to Timeline Template, width is too small to see entire field name

[MikePaquette]

Kibana version: 8.1.0 BC1

Elasticsearch version: 8.1.0 BC1

Server OS version: Elastic Cloud ESS default

Browser version: Google Chrome Version 98.0.4758.102 (Official Build) (x86_64)

Browser OS version: macOS Monterey Version 12.2.1 (21D62)

Original install method (e.g. download page, yum, from source, etc.): Elastic Cloud ESS GCP Europe-West-1

Describe the bug:
When adding a field to Timeline Template, width is too small to see entire field name

Steps to reproduce:

1. Edit a Timeline or Tempate
2. Attempt to add a field with a long name
3. Notice that you can't see the entire field name, causing the analyst to guess at what it is.

Expected behavior:
Should be able to see the entire field name.

Screenshots (if relevant):

Errors in browser console (if relevant): None

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

Any additional context: None

[elasticmachine]

Pinging @elastic/security-solution (Team: SecuritySolution)

[michaelolo24]

@monina-n thoughts on how we may want to approach fixing this. I think the current behavior is to rely on a tooltip

[elasticmachine]

Pinging @elastic/security-threat-hunting (Team:Threat Hunting)

[monina-n]

In general the width of the popover (and subsequently the dropdown) should be increased and that should account for a majority of use cases. If after we increase width, it's still not enough we can talk about other options

[logeekal]

Please see if new layout makes sense. This solves the width problem without any customization.

Old Layout	New Layout