Enhancement to sticky bottom functionality in Milo.

[aishwaryamathuria]

As a part of Milo sticky functionality enhancement for 'promobar' block MWPW-133055 we had received a request to have a certain scroll behaviour for sticky-bottom functionality when used with promobar block.
The block, when used with sticky-bottom, was supposed to show after we scroll past a section and hide at the footer.
We have received a new request for promobar now https://jira.corp.adobe.com/browse/MWPW-140011 where the new behaviour will be required but only if the author requests it with a section style. By default it would behave like Milo sticky component (always visible and sits above footer).
We have following proposal for this request and would like to get views on the same -

1. Add additional style to section 'sticky-bottom-hide' which will borrow functionality from sticky-bottom and also make the block visible after user scrolls past a section above the section with 'sticky-bottom-hide' section metadata. If author uses milo sticky-bottom with promobar, it would behave like it usually does with any other block.
2. As per the expected promobar behaviour, the block would hide as soon as the footer comes into focus if authored with 'sticky-bottom-hide'

Would appreciate some feedback on the proposal and if we should consider a different authoring for the same.

@auniverseaway @chrischrischris @rgclayton @ryanmparrish @vhargrave @overmyheadandbody @amitbikram @bandana147 @suhjainadobe @salonijain3 @dstrong23 @Ruchika4

[salonijain3]

@auniverseaway @chrischrischris @rgclayton @ryanmparrish @overmyheadandbody @narcis-radu @amitbikram
As there are no comments on this discussion, we will proceed with implementing this approach starting tomorrow. Kindly inform us of any concerns within the next day.

cc: @ccongerp @audi5 @dstrong23