[SpeedDial] - remove unecessary 'onKeyDown' prop sent to SpeedDialAction

[zanerock]

I added a 'zero warnings' unit test to catch out the error and then removed the setting of the (seemingly) no-longer-needed prop on the child SpeedDialAction children. I also manually tested on my own app.

closes #12159

[mbrookes]

@zanerock I'm not sure that this is redundant, so much as that Tooltip broke SpeedDialAction keyboard interaction at some point (#12361), so that it doesn't currently do anything. That doesn't mean it isn't needed...

[zanerock]

Thanks for the link to #12361, I get it. I expect to have time to take another run at it later this week.

[zanerock]

I took another run at fixing it, but I cannot tell what 'onKeyDown' being added by SpeedDial is doing. It looks like the only other place for it to go is the Button created by SpeedDialAction, but it's not. But if the idea from #12361 is to be able to tab to the action buttons, then the tabIndex={-1} would seem to break that. I tested manually, and I could tab to the FAB just fine, but I couldn't tab to the action buttons as expected.

@mbrookes Is it possible the problem causing #12159 (warnings from Tooltip) was introduced by a partial fix to #12361 (FAB actions not tab accessible)? It would help to know which was added first: creating the onKeyDown property for SpeedDialAction in SpeedDial or the exactProps requirement in Tooltip? I've got to run, but can check blame later...