Legend Displays Empty Labels When Adding Empty Bars to Adjust Bar Width in ngx-charts-bar-vertical

[M-Muddasir]

Bug Description
I need to reduce the width of individual bars in a single bar chart using ngx-charts-bar-vertical. Since there is no direct property to adjust bar width, I added empty bars to the dataset as a workaround (#692 (comment)). However, this causes an issue with the legend, as it displays colors for all bars, including the empty ones, along with empty labels.

Steps to Reproduce the Issue

1. Use the ngx-charts-bar-vertical component.
2. Add empty bars to the dataset to reduce the width of the existing bars. For example:

   if (data.chart_data?.length < 10) {
       const empty = '  ';
       for (let i = 0; i < 10 - data.chart_data.length; i++) {
           this.data.push({
               name: empty.repeat(i + 1),
               value: 0
           });
       }
   }

3. Save the changes and observe the issue with the legend.

Expected Behavior
Provide a property or configuration to exclude empty-value legends, ensuring the chart looks clean and the legend only reflects meaningful data.

Screenshots

ngx-charts Version
@swimlane/ngx-charts: ^20.4.1