Remove ConfigureAwait(false) in WrapAsync to avoid SynchronizationContext switch

[vanbukin]

Remove ConfigureAwait(false) to avoid switching into default SynchronizationContext.

Context

We have SpecFlow + NUnit + Allure libs in the same project. SpecFlow uses it's own SynchronizationContext. Async code that executes inside methods that marked as [AllureStep] will always switch into default SynchronizationContext.

Checklist

• [x] Sign Allure CLA
• [ ] Provide unit tests

[CLAassistant]

All committers have signed the CLA.