Fix handling engagement ended flow

[EgorovEI]

MOB-3897

What was solved?
This PR introduces endedEngagement property in Interactor for storing engagement ended by operator to fetch a survey

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.

[ykyivskyi-gl]

LGTM. Just a small note, we keep expanding the state of interactor, seems that it is good candidate for refactoring.

[EgorovEI]

LGTM. Just a small note, we keep expanding the state of interactor, seems that it is good candidate for refactoring.

@ykyivskyi-gl thanks for bringing this reasonable point. Since refactoring requires additional team discussion and preparations, I would keep it as is for now. Now it works well, but still would be good to refactor it in near future. I created the ticket for that and assigned to me.