[css-forms-1] Use better fallbacks for ::picker(select) #13541
Description
@fantasai suggests using:
position-try-fallbacks: flip-block, flip-inline, flip-block flip-inline; instead of the current fallbacks, since it flips margins/insets as well.
(So if you add margin-block-start: 10px to ::picker(), it becomes margin-bottom: 10px when the fallback is used)
Equivalent changes should be done in HTML as well.