Popover: refactor all usages of the legacy `position` prop to the `placement` prop

[ciampo]

After #40740, there are two different props in the Popover component to affect is position: position (legacy) and placement (new)

In order to deprecate the legacy position prop from the Popover component, we should first migrate all current usages to the new placement prop:

• [ ] #44387
• [ ] #44388
• [ ] #44389
• [ ] #44390
• [ ] #44391
• [ ] #44392
• [ ] #44394
• [ ] #44395
• [ ] #44396
• [ ] #44398
• [ ] #44399
• [ ] consider exporting the position-to-placement converstion utility for URLPopover, Dropdown, Tooltip and DotTip
• [ ] Dropdown (requires deprecating position in favour of placement too)
• [ ] Tooltip (requires deprecating position in favour of placement too)
• [ ] Any leftover position={ or position: props\
  • [ ] tooltipPosition prop