fix: Change networkidle2 to networkidle0

[YogeshSinghChouhan]

Switch example to networkidle0 to solve inconsistency of console messages
Fixes #2587

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[YogeshSinghChouhan]

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[aslushnikov]

This might make the race less bad, but it doesn't fix it.
Instead, we should await the event from the page, and then close the browser.

Feel free to send a separate PR for this.

[YogeshSinghChouhan]

@aslushnikov i didn't understand your point ,i think we are awaiting the event and afterwards browser is closing. Please correct me , if i understood it wrong

[aslushnikov]

@YogeshSinghChouhan The solution that waits for networkidle0 might mostly work but gives no guarantees: how's network idleness related to app-ready event?

The inconsistency happens because we sometimes close the browser before the app-ready event is dispatched. To fix the race condition the right way, we should wait for the app-ready event explicitly and then close the browser.

On a second thought, it doesn't hurt to land this CL since it makes things better without much effort, so I'll just merge it in.