[CLIENT-7686] Add `low-audio-level` detection.

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Pull Request Details

JIRA link(s):

CLIENT-7686

Description

This PR adds silence detection to the InputTest. The logic of silence detection is as follows: Find at least 3 seconds worth of volume samples. Calculate the standard deviation of the samples. If the standard deviation is <= 2.55 (1% of the max of 255), then we have constantAudio If we have constantAudio and the average of those samples is also <= 2.55, then we have low audio.

Burndown

Before review

[x] Updated CHANGELOG.md if necessary
[x] Added unit tests if necessary
[x] Updated affected documentation
[x] Verified locally with npm test
[x] Manually sanity tested running locally
[x] Included screenshot as PR comment (if needed)
[x] Ready for review

Before merge

[ ] Got one or more +1s
[ ] Re-tested if necessary

twilio / rtc-diagnostics