Convert old and inline integration tests

[THardy98]

What was changed

Refactoring old integration tests to use integration helpers.
Extended existing integration helpers to allow for configurable test contexts.

Why?

Establish more consistency with our testing.

Checklist

I'm treating this like a remaining TODO list:

• there are still a number of testing files that need to be converted to use the integration testing helpers (for separate PRs)
• we would like to organize our test workflows, activities, and definitions into targeted concerns (i.e. child workflows, signal workflows, etc.). This will make it easier to discern the purpose of each testing file and provide some visibility into our test coverage (separate PR)

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1. Closes [Feature Request] Complete conversion of old style integration tests #1569

2. How was this tested:
   Existing tests do not break

3. Any docs updates needed?
   No

[THardy98]

The main change is the pattern used in test-integration-new (I'll rename this file) to run tests over multiple test environments, and the supporting changes in helpers-integration.

Aside from that it's mostly converting tests to use the integration helpers and removing a number of single-use workflows.

I've left a small comment in workflows/index.ts noting that the filenames could make for a good start in terms of organizing our tests into more specific areas (the filenames are usually prefixed with these areas, like child, or signal, or cancel).

We can also use the shared workflows imported in test-integration-new to identify test files that are potentially similar (or at least common testing areas across multiple files), which we can then group or synthesize. As we convert other test files in this manner, it'll be increasingly clear where the commonalities lie.