Add RTCOutboundRtpStreamStats.contentType to w3c_rtc.js.
Add RTCOutboundRtpStreamStats.contentType to w3c_rtc.js.

PiperOrigin-RevId: 487610698

google/closure-compiler,monetate/closure-compiler,google/closure-compiler,google/closure-compiler,monetate/closure-compiler,monetate/closure-compiler,monetate/closure-compiler,google/closure-compiler