Isolated point styles override user defined point styles in timelion

[nickofthyme]

Kibana version:

Added in v8.9.0 via #159082

Describe the bug:

In timelion and any app/vis that uses @elastic/charts, when you have sparse data that has isolated points (a finite point between two infinite points such as null) and you override the areaSeriesStyle or lineSeriesStyle on a chart, the isolatedPoint styles take precedence without merging with the defined point styles.

Steps to reproduce:

1. Download the kibana sample data logs
2. Create a timelion vis using this expression...

.es(index=kibana_sample_data_logs,metric=sum:bytes,),
.es(index=kibana_sample_data_logs,metric=sum:bytes)
    .if(operator=gt, if=100000, then=.es(index=kibana_sample_data_logs,metric=sum:bytes), null)
    .points(radius=5)

4. Set the time picker the last 7 days
5. Notice some of the points are small while most are big (i.e. 5px radius).

Expected behavior:

Isolated point styles are merged with point style defaults.

Screenshots (if relevant):

Any additional context:

Elastic charts issue here 👉🏼 elastic/elastic-charts#2277

[elasticmachine]

Pinging @elastic/kibana-visualizations (Team:Visualizations)

[stratoula]

Thank you for contributing to this issue, however, we are closing this issue due to inactivity as part of a backlog grooming effort. If you believe this feature/bug should still be considered, please reopen with a comment.

[nickofthyme]

This will actually be fixed when elastic charts is updated to include elastic/elastic-charts#2277