Hovering over series in legend for LineSeries' doesn't reduce opacity of dot of other series

[cchaos]

Describe the bug
When mousing over the legend the currently hovered series stays at full opacity while the other series reduce opacity. However when the non-hovered series is a LineSeries, only the line's opacity reduces, the dot stays at full opacity.

To Reproduce
Steps to reproduce the behavior:

1. Create a chart with several LineSeries
2. Hover legend

Expected behavior
The dot and the line should be grouped and then whole group's opacity should be reduced

Screenshots

Version (please complete the following information):

• Elastic Charts: 8.1.5

[markov00]

🎉 This issue has been resolved in version 9.2.0 🎉

The release is available on:

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

Your semantic-release bot 📦🚀

[cchaos]

@markov00 Thanks for tackling this one so quickly. However, I think there's still an issue of grouping the line with the dot. When the dot becomes transparent you can see the line behind it and the graph starts to become very noisy.

So in the example from your PR, it should actually be: