function isDropdownsStateEqual(prevState, newState) {
  return (
    prevState.isOpen === newState.isOpen &&
    prevState.inputValue === newState.inputValue &&
    prevState.highlightedIndex === newState.highlightedIndex &&
    prevState.selectedItem === newState.selectedItem
  )
}
Check if a state is equal for dropdowns, by comparing isOpen, inputValue, highlightedIndex and selected item.
Used by useSelect and useCombobox.

@param {Object} prevState
@param {Object} newState
@returns {boolean} Wheather the states are deeply equal.