[iOS] Add withEnableSampleProfiling(true) to makeRuntimeConfig

Summary:
This enables us to use Hermes sampling profiler. Without this change we were getting facebook::jsi::JSINativeException: Runtime not registered for profiling when trying to do a Hermes sample profiling session.

Conveniently this isn't really documented (anywhere I could find), but was able to figure it out searching through hermes and react-native sources on GitHub.

Test Plan:
Here's an example:

Reviewers: ashoat, ginsu, tomek, bartek, rohan

Reviewed By: ashoat

Differential Revision: https://phab.comm.dev/D9233