fix: Braille output is empty for scatter plot

[soundaryakp1999]

Bug Report

Description

The braille output of a scatterplot is empty as tested in JAWS and NVDA.

Steps to Reproduce

1. Open examples/scatter_plot.html.
2. Focus the maidr representation with screen reader.
3. press 'b' to toggle brialle mode on.
4. no braille is displayed. According to the documentation, the line plot layer should be represented.

Actual Behavior

Braille display output is empty.

Expected Behavior

The encoding for the line layer should be displayed.

Screenshots

Environment

• Operating System: Windows 11.
• Browser: Edge
• Version: 145.0.3800.97

Additional Information