Toast notifications not animating on entry

[pling-scottlogic]

Reproduction Steps

1. Run and open the sample app
2. Save a layout

Expected Behaviour

"Layout Saved Successfully" toast notification appears on screen, with transition animation from the right.

Actual Behaviour

"Layout Saved Successfully" toast notification appears on screen, with no transition animation.

Notes

This is likely to be a more general problem with toast notifications, and should be tested against any other mechanisms for triggering them. It should also be tested in both the sample app and showcase.

[pling-scottlogic]

External PR