[ILM] Refactor edit policy helpers

[yuliacech]

The file x-pack/plugins/index_lifecycle_management/__jest__/client_integration/edit_policy/edit_policy.helpers.tsx currently consist of more than 400 lines. The amount of helper functions is very large which makes for poor maintenance:

• problem of forgetting to delete helpers when the form changes/tests are being deleted
• risk of adding similar helpers
• low discoverability of helpers functions
• tests don't need to create all available helpers on setup

On the other hand, it's straightforward to use one single function to setup an edit policy test bed for client integration tests.

After a discussion with @jloleysens, these are suggestions to refactor the file:

• extract helper functions into separate files that would contain logical groups of functions, for example node allocation helpers, timeline helpers etc
• change setup function to be a factory function accepting an array of helpers initializing functions. That way setup function doesn't know about concrete form actions, only test files know which form actions they need to initialize.

[elasticmachine]

Pinging @elastic/es-ui (Team:Elasticsearch UI)

[cjcenizal]

See #96111 (comment) for some additional context and a reference to some changes I made in support of this issue.

[yuliacech]

This was addressed in #102383.