recording: create timers in the main thread since it requires a run loop

[marandaneto]

💡 Motivation and Context

https://posthog.slack.com/archives/C07JEE5CQF2/p1725894061542169?thread_ts=1724245423.990689&cid=C07JEE5CQF2

If you init the SDK from a background task (eg a Queue, or a Task), the timers won't fire.

Run Loop Requirement: Timer.scheduledTimer needs to be associated with a run loop in order to function. If you call Timer.scheduledTimer from a background thread, it will be scheduled on the run loop of that thread. However, background threads typically don’t have run loops running by default, so unless a run loop is manually created and running on that thread, the timer won’t fire.

💚 How did you test it?

Running from a task

📝 Checklist

• I reviewed the submitted code.
• I added tests to verify the changes.
• I updated the docs if needed.
• No breaking change or entry added to the changelog.