Configurable maxTextSize

[lourd]

Hi, thanks for the great work on this extension!

Is it possible to configure the maxTextSize? I have a diagram that exceeds the default limit, causing the "Maximum text size in diagram exceeded" error. I tried adding the configuration as frontmatter, as mentioned in the docs https://mermaid.js.org/config/configuration.html#frontmatter-config

---
config:
  maxTextSize: 500000
---

but that doesn't seem to work.