Setup and teardown integ tests' dependencies effectively

We should consider how we might effectively setup and teardown these integ tests' dependent environments in `integ/util.go:dostartIwfServiceWithClient` to achieve this in the future.

`integ/util.go:dostartIwfServiceWithClient` AFAICT sets up the iwf process and connection to the backing provider(cadence/temporal) for each test. We may be able to expand on this to track all started wf's and make sure they are closed on each test execution such that we don't have to explicitly add this behavior to each test in the future.

_Originally posted by @bowersj27 in https://github.com/indeedeng/iwf/pull/540#pullrequestreview-2596900819_

Start with integ/util.go:dostartIwfServiceWithClient and inspect how each integration test starts the iWF process and connects to its backing provider. Define how started workflows and dependent environments should be tracked and cleaned up per test, with completion shown by removing the need for each test to manage that behavior explicitly.

Written by the indexing model from the issue text.