[7.x] [Security Solution][Case] ServiceNow ITSM: Add category & subcategory fields (#90547)

[cnasikas]

Backports the following commits to 7.x:

• [Security Solution][Case] ServiceNow ITSM: Add category & subcategory fields ([Security Solution][Case] ServiceNow ITSM: Add category & subcategory fields #90547)

[kibanamachine]

💚 Build Succeeded

• continuous-integration/kibana-ci/pull-request
• Commit: 6f39b6c

Metrics [docs]

Module Count

Fewer modules leads to a faster build time

id	before	after	diff
securitySolution	2180	2181	+1
triggersActionsUi	338	339	+1
total			+2

Async chunks

Total size of all lazy-loaded chunks that will be downloaded as the user navigates the app

id	before	after	diff
securitySolution	7.5MB	7.5MB	+3.8KB
triggersActionsUi	1.4MB	1.4MB	+3.4KB
uptime	909.2KB	909.2KB	+31.0B
total			+7.2KB

Page load bundle

Size of the bundles that are downloaded on every page load. Target size is below 100kb

id	before	after	diff
securitySolution	234.0KB	234.1KB	+105.0B

To update your PR or re-run it, just comment with:
@elasticmachine merge upstream