Resolve "copy markdown from comments does often only copy alt value of images"

What does this MR do?

Copying and pasting markdown content wasn’t working for DOM elements which have no text content, eg: image tag.

This commit will fix it.

Screenshots

Before	After

Does this MR meet the acceptance criteria?

Conformity

• Changelog entry
• Documentation (if required)
• Code review guidelines
• Merge request performance guidelines
• Style guides
• Database guides
• Separation of EE specific content

Mentions #24020 (closed)