[8.6] [@kbn/handlebars] Add support for partials (#150151)

[kibanamachine]

Backport

This will backport the following commits from main to 8.6:

• [@kbn/handlebars] Add support for partials (#150151)

Questions ?

Please refer to the Backport tool documentation

[github-actions]

Documentation preview:

• ✨ Changed pages

[kibana-ci]

💚 Build Succeeded

• Buildkite Build
• Commit: c48853d

Metrics [docs]

Public APIs missing comments

Total count of every public API that lacks a comment. Target amount is 0. Run node scripts/build_api_docs --plugin [yourplugin] --stats comments for more detailed information.

id	before	after	diff
@kbn/handlebars	12	14	+2

Async chunks

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

id	before	after	diff
canvas	1.0MB	1.0MB	+2.1KB
uiActionsEnhanced	138.8KB	140.9KB	+2.1KB
visTypeTimeseries	511.6KB	513.7KB	+2.1KB
total			+6.2KB

Unknown metric groups

API count

id	before	after	diff
@kbn/handlebars	19	21	+2

ESLint disabled in files

id	before	after	diff
osquery	1	2	+1

ESLint disabled line counts

id	before	after	diff
@kbn/handlebars	4	5	+1
enterpriseSearch	19	21	+2
fleet	61	67	+6
osquery	108	113	+5
securitySolution	441	447	+6
total			+20

Total ESLint disabled count

id	before	after	diff
@kbn/handlebars	8	9	+1
enterpriseSearch	20	22	+2
fleet	69	75	+6
osquery	109	115	+6
securitySolution	518	524	+6
total			+21

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

cc @watson