ACTION-756: Write to webaudio asking if they did a self-review

From https://www.w3.org/TR/mediacapture-streams/#dom-mediastream ... "When a MediaStream is created, the User Agent MUST generate an identifier string, and MUST initialize the object's id attribute to that string, unless the object is created as part of a special purpose algorithm that specifies how the stream id must be initialized. A good practice is to use a UUID [rfc4122], which is 36 characters long in its canonical form. To avoid fingerprinting, implementations SHOULD use the forms in section 4.4 or 4.5 of RFC 4122 when generating UUIDs."