`HeatmapVis`: white border in dark mode for pixels with `ignoreValue`

[stufisher]

Describe the bug

When using ignoreValue in conjunction with dark mode and HeatmapVis, there seems to be a white border on the top / bottom of the relative pixel.

Screenshots

Context

• OS: osx
• Browser: chrome 131, firefox 132
• Version: 13
• H5Web context: @h5web/lib

[stufisher]

FYI, if i very slightly resize the browser it goes away. Subpixel rendering maybe?