feat: Use ListenerItemExpectations for customer cancel

[lukehesluke]

Implements #698 for customer-requested cancellations

QA

I tested this against a booking system which is not yet stable, but was able to gain confidence that the feature works as expected.

These screenshots demonstrate some of this. They are a side-by-side comparison of the results for the book-and-cancel test. The LHS includes the changes and the RHS does not:

Single mode:

Here, the booking system failed to produce the CustomerCancelled order feed change in the LHS test, but this lead to it failing at the order feed download step, as it could never be found. Whereas, in the RHS test, Test Suite passes the order feed download step but then later fails when asserting about orderItemStatuses

Multiple mode:

Here, the booking system succeeded in producing the CustomerCancelled order feed change, and so the LHS test passed (except an unrelated validation issue), whereas the RHS did not, because Broker latched onto an irrelevant order feed update (this booking system is one that produces such updates)

[lukehesluke]

Bookteq/Vivify: Expand ListenerItemExpectations to customer-requested cancellations

[nickevansuk]

Looks good!