Checklist

• I have searched the existing issues for similar issues.
• I added a very descriptive title to this issue.
• I have provided sufficient information below to help reproduce this issue.

Summary

Version 1.21.0 appears to have a bug causing st.code blocks to not render correctly because 3 middle DIVs are missing (stMarkdown, stMarkdownContainer, stCodeBlock)

Reproducible Code Example

import streamlit as st

st.code("Hello world", language=None)

Steps To Reproduce

Run code
Try to mouseover to copy code (doesn't work)
Inspect element and see that a couple DIVs are missing vs doing the same thing in v1.20.0 (e.g., stMarkdown, stMarkdownContainer, stCodeBlock)

Expected Behavior

Mousover works to copy code
stMarkdown, stMarkdownContainer, stCodeBlock DIVs exist to aid with custom CSS

Current Behavior

No response

Is this a regression?

• Yes, this used to work in a previous version.

Debug info

• Streamlit version: 1.21.0
• Python version: 3.11-slim
• Operating System: ChromeOS
• Browser: Chrome
• Virtual environment: GitHub Codespaces

Additional Information

No response

Are you willing to submit a PR?

• Yes, I am willing to submit a PR!