RUM-4591 chore: Add diagnostic attributes to "RUM Session Ended" telemetry

[ncreated]

What and why?

📦 🔭 According to the spec (internal), this PR adds "diagnostic attributes" to "RUM Session Ended" telemetry.

This is a follow-up on #1866 where we implemented a handset of "quality attributes".

How?

The list of added attributes:

rse.has_background_events_tracking_enabled

Indicates whether tracking of background events was enabled in the RUM configuration.

rse.views_count.by_instrumentation

Holds the map of instrumentation type to the number of distinct views (view UUIDs) tracked through it (manual | swiftui | uikit).

rse.views_count.with_has_replay

The number of views with has_replay == true.

rse.ntp_offset

The NTP offset at the beginning and end of the session.

rse.no_view_events_count

The number of events (actions | resources | errors | long_tasks) dropped because there was no active view at the time they occurred.

Review checklist

• Feature or bugfix MUST have appropriate tests (unit, integration)
• Make sure each commit and the PR mention the Issue number or JIRA reference
• Add CHANGELOG entry for user facing changes

Custom CI job configuration (optional)

• Run unit tests for Core, RUM, Trace, Logs, CR and WVT
• Run unit tests for Session Replay
• Run integration tests
• Run smoke tests
• Run tests for tools/

[datadog-datadog-prod-us1]

Datadog Report

Branch report: ncreated/RUM-4591/send-diagnostic-attributes-in-session-ended-telemetry
Commit report: 8551142
Test service: dd-sdk-ios

❌ 1 Failed (0 Known Flaky), 1490 Passed, 0 Skipped, 1m 21.09s Total Time
⬆️ Test Sessions change in coverage: 4 increased, 2 no change

❌ Failed Tests (1)

• testParentSpanPropagation - NetworkInstrumentationIntegrationTests - Details

  Expand for error

   
   Assertion Failure at NetworkInstrumentationIntegrationTests.swift:79: XCTAssertEqual failed: ("urlsession.request") is not equal to ("root")
   Assertion Failure at NetworkInstrumentationIntegrationTests.swift:81: XCTAssertEqual failed: ("Optional(DatadogInternal.SpanID(rawValue: 101))") is not equal to ("Optional(DatadogInternal.SpanID(rawValue: 100))")
   Uncaught Exception at NetworkInstrumentationIntegrationTests.swift:82: XCTAssertEqual failed: threw error "Exception(description: "No value for key path \`metrics._top_level\`")"
   Assertion Failure at NetworkInstrumentationIntegrationTests.swift:85: XCTAssertEqual failed: ("root") is not equal to ("urlsession.request")
   Assertion Failure at NetworkInstrumentationIntegrationTests.swift:87: XCTAssertEqual failed: ("Optional(DatadogInternal.SpanID(rawValue: 0))") is not equal to ("Optional(DatadogInternal.SpanID(rawValue: 100))")
   Assertion Failure at NetworkInstrumentationIntegrationTests.swift:88: XCTAssertEqual failed: ("Optional(DatadogInternal.SpanID(rawValue: 100))") is not equal to ("Optional(DatadogInternal.SpanID(rawValue: 101))")
  

[ganeshnj]

A more fundamental question on choice of type in the PR. The changes looks good.