Decouple connector creation for FF tests

[ohltyler]

Description

Improves the Flow Framework OSD plugin tests by decoupling the connector creation step for improved flexibility & less flakiness when running the tests against different endpoints with different security standards. For example, an Amazon OpenSearch Service (AOS) domain prohibits remote connector creation, so these tests cannot run out-of-the-box against such endpoints. This fixes that, by mocking the connector creation entirely if the step fails.

Includes several other minor improvements to minimize flakiness, such as the model deployment call and scoped-down mocking checks during ingest and search.

Tested against local domain with no security, and against an AOS domain with basic auth. Both scenarios succeed without any changes to the test file:

       Spec                                              Tests  Passing  Failing  Pending  Skipped  
  ┌────────────────────────────────────────────────────────────────────────────────────────────────┐
  │ ✔  plugins/dashboards-flow-framework/c      02:41        6        6        -        -        - │
  │    reate_workflow_spec.js                                                                      │
  └────────────────────────────────────────────────────────────────────────────────────────────────┘
    ✔  All specs passed!                        02:41        6        6        -        -        -  

Issues Resolved

Check List

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