Fix explain code text selection for unsupported languages
What does this MR do and why?
Ensures content that cannot be highlighted by highlight.js is rendered as plain text.
Screenshots or screen recordings
Screenshots are required for UI changes, and strongly recommended for all other merge requests.
| Before | After |
|---|---|
 |
 |
How to set up and validate locally
- Enable the explain code feature flags
- Open source code that cannot be highlighted by highlight.js (sample.vue)
- Select the content and click the explain code button
- The selected content should be rendered as plain text
MR acceptance checklist
This checklist encourages us to confirm any changes have been analyzed to reduce risks in quality, performance, reliability, security, and maintainability.
-
I have evaluated the MR acceptance checklist for this MR.
Related to #416366 (closed)