How to remove blank data in Bar chart in PowerBI after selecting option in first chart

By default, Power BI cross highlights from one chart on a page to another. If you selected a specific area from your slicer, everything would filter. You can mimic this behavior by clicking on the charts too, you just need to change the behavior to filtering instead of cross-highlighting. Select your first chart, then click the Format ribbon at the top and select Edit interactions.

You will see these icons over your other visuals on the page:

The middle shaded one indicates that when you touch the first chart, it will cross-highlight this visual. If you select the first icon instead, it will filter.

Here is an example I have:

When I click the bar on the top left visual, it cross highlights the lower right:

Now, if I change the interaction to filter instead... BOOM! Lower right is just showing what I have selected in upper left.

Here's some documentation as well: Change how visuals interact in a report - Power BI | Microsoft Learn