Fix RAC submenu flipping (#5808)
* fix submenu flip positioning
we need to wait til the collection is computed, otherwise the overlay has a height of 0 and we get an inaccurate position due to a premature max height being applied
* updating the container padding for the submenu in RAC
if we let the default of 12 get applied, the positioning is slightly strange when submenu trigger is at the bottom of the boundary
* clear the max height on the overlay so we always get a proper position calculation on every render
* forgot to reset some changes
* adding a comment for posterity
* revert containerPadding set
