fix(crosshair): hide horizontal line when the pointer is outside chart

[markov00]

Summary

This commit fix the visibility of the crosshair horizontal line, hiding
it when the pointer projected position is outside the chart area.

fix #483

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

[codecov-io]

Codecov Report

Merging #484 into master will decrease coverage by 0.07%.
The diff coverage is 100%.

@@            Coverage Diff            @@
##           master    #484      +/-   ##
=========================================
- Coverage   83.77%   83.7%   -0.08%     
=========================================
  Files         158     169      +11     
  Lines        4703    4853     +150     
  Branches      952     966      +14     
=========================================
+ Hits         3940    4062     +122     
- Misses        748     775      +27     
- Partials       15      16       +1

Impacted Files	Coverage Δ
..._types/xy_chart/state/selectors/get_cursor_line.ts	100% <ø> (ø)	⬆️
...rc/chart_types/xy_chart/renderer/dom/crosshair.tsx	80.85% <ø> (-2.13%)	⬇️
.../chart_types/xy_chart/crosshair/crosshair_utils.ts	93.4% <100%> (+0.22%)	⬆️
src/mocks/series/series.ts	81.96% <0%> (ø)
src/mocks/specs/specs.ts	66.66% <0%> (ø)
src/mocks/scale/index.ts	100% <0%> (ø)
src/mocks/index.ts	100% <0%> (ø)
src/mocks/series/index.ts	100% <0%> (ø)
src/mocks/series/seriesIdentifiers.ts	93.33% <0%> (ø)
... and 5 more

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[nickofthyme]

Looks great!

[markov00]

🎉 This PR is included in version 15.0.2 🎉

The release is available on:

• GitHub release
• npm package (@latest dist-tag)

Your semantic-release bot 📦🚀