Summary

it's a partial fix for the scrollbar PR.

if you comment out the changes done in tooltip/utils.ts and portal
you can see the current behavior of the "red" portal: we need to "switch" the portal when the portal is overflowing the chart edge. The current behavior instead take into consideration the tooltip width and not the portal width.

This fix add an anchor point to anchor the tooltip at the left or right of the portal depending if we flipped the portal to the right or left of the mouse position

Checklist

Use strikethroughs to remove checklist items you don't feel are applicable to this PR.

• Any consumer-facing exports were added to src/index.ts (and stories only import from ../src except for test data & storybook)
• This was checked for cross-browser compatibility, including a check against IE11
• Proper documentation or storybook story was added for features that require explanation or tutorials
• Unit tests were updated or added to match the most common scenarios
• Each commit follows the convention