Heatmap labels are hard to see with dark theme

[drewdaemon]

Describe the issue
When EUI_CHARTS_THEME_DARK is used as the theme for a heatmap (per these directions), the labels are very dark.

To Reproduce
Sandbox

Expected behaviour
The labels should be light enough to contrast with the background.

Screenshots

Version (please complete the following information):

• OS: OSX
• Browser: Brave, Edge, etc
• Elastic Charts: 64.0.0

[nickofthyme]

Thanks @drewdaemon, that usage is no longer the ideal approach as we are deprecating the theme consumed from eui in favor of our new charts LIGHT_THEME and DARK_THEME from #2175. My next task is to update the eui docs and exports to reflect this change.

[drewdaemon]

@jpcarey see the above guidance to resolve your issue with the dark theme on the heatmap vis. Try importing LIGHT_THEME and DARK_THEME from the charts library instead of using the EUI themes.

[nickofthyme]

Also see elastic/kibana#170914 (comment) for changes applied to kibana.

[nickofthyme]

Closing as we are updating the eui docs to reflect this change in elastic/eui#7572

[jpcarey]

That worked, thank you @nickofthyme and @drewdaemon