[8.x] chore(slo): remove deprecated theme provider and usage of styled-components (#200248)

[kibanamachine]

Backport

This will backport the following commits from main to 8.x:

• chore(slo): remove deprecated theme provider and usage of styled-components (#200248)

Questions ?

Please refer to the Backport tool documentation

[elasticmachine]

Pinging @elastic/obs-ux-management-team (Team:obs-ux-management)

[github-actions]

🤖 GitHub comments

Expand to view the GitHub comments

Just comment with:

• /oblt-deploy : Deploy a Kibana instance using the Observability test environments.
• run docs-build : Re-trigger the docs validation. (use unformatted text in the comment!)

[elasticmachine]

💛 Build succeeded, but was flaky

• Buildkite Build
• Commit: 7d03123

Failed CI Steps

• Jest Tests #7
• FTR Configs #42

Test Failures

• [job] [logs] Jest Tests #7 / #getDataUsageMetricsFiltersFromUrlParams should use given relative startDate and endDate values URL params
• [job] [logs] FTR Configs #42 / Spaces app (with solution view) space solution tour solution tour does not show the solution tour after deleting spaces and leave only the default

Metrics [docs]

Module Count

Fewer modules leads to a faster build time

id	before	after	diff
slo	869	856	-13

Async chunks

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

id	before	after	diff
slo	854.5KB	831.8KB	-22.7KB

Page load bundle

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

id	before	after	diff
slo	28.6KB	28.5KB	-95.0B

Unknown metric groups

ESLint disabled line counts

id	before	after	diff
slo	16	17	+1

Total ESLint disabled count

id	before	after	diff
slo	20	21	+1

cc @kdelemme