Component/Slot overlay is brittle if HTML comments are missing

sanket.tale → made their first commit to this issue’s fork.

Added SlotOverlay component with dynamic positioning and slot drop support.
Need help fixing the pipeline issue with image assertion in iframe during tests.

@larowlan I'm unclear what "this code" is referring to in the following:

Make this code more resilient so that every source plugin doesn't have to conform to a particular twig format in order to get the HTML comments

Do you mean make the code that inserts the HTML comments more resilient (so change that a Source plugin can render its output without using xb_slot_ids and xb_uuid but still have the Twig extension output the comments.) or are you talking about making the FE code more resilient (e.g. handle the situation where the layout/model data suggests there is a slot but the markup does not have comments)?

The code in question is parentElementInsideIframe = slotsMap[parentSlot.id].element;

The code in the MR is what I was expecting - this only happens if you write your own Source plugin and don't emit the comments.

Its failing tests so needs work