Add timeout to setTelemetry

[eliasyishak]

Closes issue:

• Use internal futures list for setTelemetry #203

Related to the flutter/flutter issue here:

• No offline check when performing various Flutter CLI steps flutter/flutter#138147

This adds a timeout to the setTelemetry method, previously it was just one event being sent so we did not add any timeouts, but if the one request we send with each opt out/in event hangs, then we should cancel it.

This does not change the underlying opt out/in functionality, it will only drop the event from being sent if the request takes too long

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