ResizeObserver isn't supported for Safari iOS versions we support.
We support iOS Safari ≥ 12.2 but ResizeObserver support requires
iOS Safari >=13.4. So if they're on iOS Safari >= 12.2 and < 13.4,
it crashes.
Tippyjs is equipped to handle reference element moving from
its initial position so that the popover moves / changes
along with the reference / window size.
