Dashboard screenshot/PDF export fails due to non-printable control characters (U+0008) in titles

[chkang-idk2]

Bug description

When a chart or dashboard title contains non-printable control characters—specifically the Backspace character (U+0008 / \x08)—the Image/PDF export feature (powered by Playwright/Selenium headless browsers) fails.

These characters are often inadvertently included when users copy and paste text from external sources (e.g., legacy systems, spreadsheets). While they are invisible on macOS, they appear as small boxes on Windows and cause the headless browser used for reports/thumbnails to hang or crash during the rendering process.

test�test

Screenshots/recordings

Superset version

6.0.0

Python version

3.11

Node version

18 or greater

Browser

Chrome

Additional context

No response

Checklist

• I have searched Superset docs and Slack and didn't find a solution to my problem.
• I have searched the GitHub issue tracker and didn't find a similar bug report.
• I have checked Superset's logs for errors and if I found a relevant Python stacktrace, I included it here as text in the "additional context" section.