GH-1607 fix: use currentRequest instead originalRequest for interception

[ganeshnj]

Fixes #1607

What and why?

Because we intercept originalRequest which could have already been mutated, we end up using a stale version of the request.

How?

Use currentRequest for interception.

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: ganeshnj/fix/gh-1607-use-current-request
Commit report: c50e81a

✅ dd-sdk-ios: 0 Failed, 0 New Flaky, 2761 Passed, 0 Skipped, 29m 6s Wall Time