[chrome] Improve breadcrumb extension

[Dosant]

Summary

fix #208728

This PR improves breadcrumb extension point for adding starring next to a dashboard breadcrumb #200315:

• Fix breadcrumb extension didn't render in solution nav
• Support multiple extensions (search sessions are deprecated and need to be enabled with kibana.yml flag, but we still need to support both UI elements)
• Improve DX to unmount the extension

To test:

• Add data.search.sessions.enabled: true and see that search session UI appears in solution nav.
• To test multiple, add more extensions by using chrome.setBreadcrumbsAppendExtension, e.g. in src/platform/plugins/shared/data/public/search/search_service.ts . This actually gonna be used in [Dashboards] Favorite a dashboard from within #200315

[elasticmachine]

Pinging @elastic/appex-sharedux (Team:SharedUX)

[tsullivan]

LGTM. It's a slew of improvements!

[jennypavlova]

Obs ux infra and services changes LGTM

[kibanamachine]

Starting backport for target branches: 8.x

https://github.com/elastic/kibana/actions/runs/13202204703

[elasticmachine]

💛 Build succeeded, but was flaky

• Buildkite Build
• Commit: b33f5af
• Storybooks Preview

Failed CI Steps

• x-pack/test_serverless/functional/test_suites/security/common_configs/config.group8.ts

Test Failures

• [job] [logs] x-pack/test_serverless/functional/test_suites/security/common_configs/config.group8.ts / lens serverless - group 1 - subgroup 6 lens logsdb smoke testing functions support Scenarios with changing stream type LogsDB downgraded to regular data stream scenarios LogsDB stream with no additional stream/index and no host.name field should visualize an annotation layer from a logsDB stream using another time field

Metrics [docs]

Module Count

Fewer modules leads to a faster build time

id	before	after	diff
core	406	407	+1

Async chunks

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

id	before	after	diff
streamsApp	295.7KB	295.7KB	-10.0B

Page load bundle

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

id	before	after	diff
core	484.3KB	484.8KB	+512.0B
observabilityShared	93.9KB	93.9KB	-10.0B
total			+502.0B

Unknown metric groups

API count

id	before	after	diff
@kbn/core-chrome-browser	210	211	+1

History

• 💛 Build #273565 was flaky 5865331

[kibanamachine]

💔 All backports failed

Status	Branch	Result
❌	8.x	Backport failed because of merge conflicts You might need to backport the following PRs to 8.x: - [Security Solution] [AI Assistant] Replace polynomial regular expression with constant time string manipulation (#209314) - [Expandable Flyout] - customize default right, left and preview widths for push mode (#206155) - [Security Solution] remove isDraggable props + various related cleanups (#207959) - [GenAI Connectors] Add support for telemetry metadata (#208180)

Manual backport

To create the backport manually run:

node scripts/backport --pr 209765

Questions ?

Please refer to the Backport tool documentation

[kibanamachine]

Friendly reminder: Looks like this PR hasn’t been backported yet.
To create automatically backports add a backport:* label or prevent reminders by adding the backport:skip label.
You can also create backports manually by running node scripts/backport --pr 209765 locally