[ML] Move statically exported code from plugins to packages

[walterra]

Follow up to #156643.

Meta issue for the effort to move code that we export statically from plugins to use packages. In some cases this can reduce the size of the ml plugin's load bundle size. In other cases we want to get rid of bundle requirements where the location of the code is semantically not related, for example, the transform plugin should not require the ml bundle.

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This section lists the files that have exports we want to remove:

• [ ] x-pack/plugins/ml/public/index.ts
• [x] x-pack/plugins/ml/public/shared.ts https://github.com/elastic/kibana/pull/193657
• [ ] x-pack/plugins/ml/server/index.ts
• [ ] x-pack/plugins/ml/server/shared.ts

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This section lists files with the imports in consuming plugins we want to remove. Depending on the use case, this means moving the original code to packages or in edge cases we also might want to expose functionality via the source plugin's start contract.

• [x] x-pack/plugins/transform/common/shared_imports.ts https://github.com/elastic/kibana/pull/193657
• [x] x-pack/plugins/transform/public/shared_imports.ts https://github.com/elastic/kibana/pull/193657
• [x] x-pack/plugins/transform/public/__mocks__/shared_imports.ts https://github.com/elastic/kibana/pull/193657
• [ ] x-pack/plugins/data_visualizer/public/application/shared_imports.ts

[elasticmachine]

Pinging @elastic/ml-ui (:ml)