[ML] Use KibanaThemeProvider in ML plugin

[peteharverson]

Summary

Adapts the ML plugin and the ML jobs page under Stack Management to use the KibanaThemeProvider implementation and the theme$ prop in toMountPoint calls.

Part of #119007 and #118866.

Checklist

• This was checked for cross-browser compatibility

[elasticmachine]

Pinging @elastic/ml-ui (:ml)

[jgowdyelastic]

Code LGTM

[peteharverson]

@elasticmachine merge upstream

[darnautov]

LGTM, just one suggestion about the dependency cache

[darnautov]

We actually can avoid using dependency cache here by passing overlays and a theme as arguments. First to MlClientLicense constructor and then to this function.

[jgowdyelastic]

MlClientLicense would need to keep a local reference to overlays and theme for use later, which is no different to the dependency cache keeping references to them.
At least with the dependency cache they are all in the same place.

[peteharverson]

Fair point. @jgowdyelastic and I discussed this and decided that keeping a copy in the cache rather than a copy in the licence is simpler for now.

[kibana-ci]

💚 Build Succeeded

• Buildkite Build
• Commit: 3fa8e85
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Metrics [docs]

Async chunks

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

id	before	after	diff
ml	3.5MB	3.5MB	+726.0B

Page load bundle

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

id	before	after	diff
ml	38.3KB	38.5KB	+162.0B

History

• 💚 Build #12402 succeeded 92e4982

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

cc @peteharverson