Docs: Invalid Data Types Added to Demo

[tjuranek]

Describe the bug On the synchro chart docs demo page page, invalid data will be added to the chart when clicking 'Add Data' a few times.

To Reproduce Steps to reproduce the behavior:

1. Go to synchro chart docs demo page page.
2. Click on 'Add Data' twice
3. Data type error appears on line chart

Expected behavior Only valid data should be added to the chart.

Screenshots

Desktop (please complete the following information):

• OS: MacOS Monterey 12.6.1
• Browser: Chrome
• Version: 109.0.5414.87