Add logs for unknown onEnd engagement action

[ykyivskyi-gl]

What was solved?
This PR adds logs for unknown onEnd engagement action

Release notes:

• Feature
• Ignore
• Release notes (Is it clear from the description here?)
• Migration guide (If changes are needed for integrator already using the SDK - what needs to be communicated? Add underneath please)

Additional info:

• Is the feature sufficiently tested? All tests fixed? Necessary unit, acceptance, snapshots added? Check that at least new public classes & methods are covered with unit tests
• Did you add logging beneficial for troubleshooting of customer issues?
• Did you add new logging? We would like the logging between platforms to be similar. Refer to Logging from iOS SDKs → Things to consider for newly added logs in Confluence for more information.

[igorkravchenko]

Since the log is managed dependency, it would be probably not very hard to add unit test for case let .unknown(unhandledCase). Does it make sense?

[ykyivskyi-gl]

!squash

[ykyivskyi-gl]

@igorkravchenko I am not a big fan of testing logs but I think you are right in this case, it makes sense to cover unknown enum cases logs with tests. Thanks!