RUM-4086 Synchronize SR info with WebViews

[maxep]

What and why?

This fixes some discrepancies between the Webview and host app content regarding Session Replay.

Same as DataDog/dd-sdk-android#1990

How?

• The _dd.session.plan field has been deprecated and should be removed
• The session.has_replay and _dd.replay_stats fields should be discarded from the webview RUM event if SR is disable in the host application, to avoid orphan SR sessions

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: maxep/RUM-4086/inject-has-replay-to-browser-event
Commit report: 5d3a8dd
Test service: dd-sdk-ios

✅ 0 Failed, 2799 Passed, 0 Skipped, 24m 22.75s Wall Time
🔻 Test Sessions change in coverage: 12 decreased, 2 increased

🔻 Code Coverage Decreases vs Default Branch (12)

This report shows up to 5 code coverage decreases.

• test DatadogRUMTests tvOS 80.82% (-0.21%) - Details
• test DatadogCoreTests tvOS 79.45% (-0.17%) - Details
• test IntegrationScenarios 3.51% (-0.17%) - Details
• test DatadogInternalTests iOS 80.08% (-0.08%) - Details
• test DatadogTraceTests tvOS 49.48% (-0.06%) - Details

[maciejburda]

LGTM