new(tooltip, xychart): force update TooltipInPortal bounds

[williaster]

🚀 Enhancements

This PR fixes an issue with XYChart's Tooltip described in #983, where Tooltip position does not correctly update when the chart container changes position due to limitations with react-use-measure (note that position does update upon page scroll or container resize). It's not obvious how to fix this with IntersectionObserver, etc. so I used a relatively simple approach:

• expose react-use-measure's forceRefreshBounds function in the @visx/tooltip useTooltipInPortal hook, which will force update the Tooltip container bounds
• invoke ^forceRefreshBounds whenever @visx/xychart's Tooltip goes from the unopen => open state

Closes #983.

Before
In this case, the chart animates in from the left so the Portal thinks its bounds are way left/off screen until I scroll, at which point react-use-measure updates the position and the tooltip is correctly positioned; see #983 for a different example with drag & drop

After
Tooltip has correct position from the outset

@kristw @hshoff
cc @valtism

[coveralls]

Pull Request Test Coverage Report for Build 535116481

• 6 of 7 (85.71%) changed or added relevant lines in 2 files are covered.
• No unchanged relevant lines lost coverage.
• Overall coverage increased (+0.08%) to 61.824%

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Changes Missing Coverage	Covered Lines	Changed/Added Lines	%
packages/visx-tooltip/src/hooks/useTooltipInPortal.tsx	0	1	0.0%

Totals
Change from base Build 516508911:	0.08%
Covered Lines:	1791
Relevant Lines:	2758

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💛 - Coveralls

[valtism]

Amazing! Thank you

[VigneshTrantor]

Thank you