Update stack-trace-api.md

[php4fan]

Added that setting Error.stackTraceLimit = undefined also disables stack traces like setting it to zero does.

I suspect that is true for any non-number value (and also negative numbers, but that is implicit in the statement that any finite integer defines the maximum), but I can only say for sure it's the case for undefined.

Note that at some point in the past setting it to undefined used to have the same effect that Infinity has now. I'm not sure when that changed, it may have been many years ago, but at some point it was true, at least in Chrome.

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[camillobruni]

Could you sign the CLA to land your PR? https://cla.developers.google.com/. Thanks!

[php4fan]

Could you sign the CLA to land your PR?

I already did