If the camera track has already ended by the time the blur processor is
applied to it, MediaStreamTrackProcessor cannot be constructed and
setProcessor rejects. Both call sites used `void`, so this surfaced as
Unhandled promise rejection: TypeError: Failed to construct
'MediaStreamTrackProcessor': Input track cannot be ended
(element-call-rageshakes#17225). Skip ended tracks, and catch and log
processor attach/detach failures instead of leaking them.
The throttled flush callback returned this.flush instead of calling it
(regressed in #2607), so logs were only persisted to IndexedDB on
rageshake submission or beforeunload. When the host removes the widget
iframe at hangup, the whole call's logs were lost, so a rageshake filed
from a later call carries nothing from the affected one.
Matthew Hodgson