MDL-70075 core: Listen for change in accessibleChange event

The accessibleChange custom interaction event was only listening for
blur and focus, however some OS/browser combinations do not emit these
events until the element is explicitly blurred. This is notably
different on Firefox on some Operating Systems.

Recent changes in MDL-68167 explicitly moved the user participants page
filter module to use the accessibleChange event, which means that the
selections are now only triggered on an explicit blur when using
Firefox. This highlight a bug whereby, when the mouse is used to make a
selection, the event is not triggered until the element is blurred.

This change modifies the accessibleChange event to ignore the `change`
event where it was triggered by the keyboard and where that keybaord
event was not a [return] or [escape] keypress, but to otherwise respect
the native change event.