Add enableSoftLineBreaks to shared-ux-markdown

[sakurai-youhei]

Summary

This PR adds an enableSoftLineBreaks parameter to the <Markdown> component in shared-ux, which enables it to fill the gap in line breaking between the legacy React <Markdown> component.

The parameter defaults to false not to change the current behavior in existing use cases. Furthermore, there is currently no case where the parameter is set to true because of #180906.

Closes #180576

Checklist

• This was checked for cross-browser compatibility

For maintainers

• This was checked for breaking API changes and was labeled appropriately

[kibana-ci]

💚 Build Succeeded

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• Commit: 107158d
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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/shared-ux-markdown-mocks	31	40	+9

Async chunks

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

id	before	after	diff
apm	3.2MB	3.2MB	+33.0B
controls	231.3KB	231.4KB	+99.0B
discover	636.4KB	636.5KB	+33.0B
expressionError	14.4KB	14.4KB	+33.0B
lens	1.4MB	1.4MB	+33.0B
textBasedLanguages	167.3KB	167.3KB	+33.0B
visTypeTimeseries	512.6KB	512.7KB	+33.0B
visualizations	285.6KB	285.6KB	+33.0B
total			+330.0B

Page load bundle

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

id	before	after	diff
banners	10.4KB	10.4KB	+33.0B
presentationPanel	43.2KB	43.2KB	+33.0B
total			+66.0B

Unknown metric groups

API count

id	before	after	diff
@kbn/shared-ux-markdown-mocks	32	41	+9

History

• 💛 Build #208985 was flaky c731b21
• 💚 Build #208023 succeeded fa92dfa

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