Use HTMLMediaElement.play() on video assignment

This is a bit of a long-shot debugging attempt; but when I've inspected
the state of a frozen KCMA app, the stream had never been told to play.
I don't know that I've been able to interpret the debug messages.

There's an autoPlay set, but I'm not clear enough about the ordering of
how the events fire; so I'm going to add this to avoid doubt; and the
ancidata of smashing f5 has been helpful in seeing the play message get
to the stream now.

Signed-off-by: Paul R. Tagliamonte <paul@kittycad.io>

src/components/Stream.tsx

@@ -41,7 +41,9 @@ export const Stream = ({ className = '' }) => {
       return
     if (!videoRef.current) return
     if (!mediaStream) return
+    console.log('setting video ref')
     videoRef.current.srcObject = mediaStream
+    videoRef.current.play()
   }, [mediaStream, engineCommandManager])
 
   const handleMouseDown: MouseEventHandler<HTMLVideoElement> = ({