Feat: DO-3456 extract code from markdown and use code viewer in chat component

[patricia-causalens]

Motivation and Context

Improve the visuals of code blocks rendered within Chat component, and allow users to easily copy its content

Implementation Description

Added a parser that breaks the message string into Markdown and CodeViewer components. This is only applied to the displayed message so that when editing users still have full control of the markdown string and can make changes if needed

Updated base markdown component to use CodeViewer for code blocks with a specified language.

Any new dependencies Introduced

How Has This Been Tested?

Locally on storybook

PR Checklist:

• I have implemented all requirements? (see JIRA, project documentation).
• I am not affecting someone else's work, If I am, they are included as a reviewer.
• I have added relevant tests (unit, integration or regression).
• I have added comments to all the bits that are hard to follow.
• I have added/updated Documentation.
• I have updated the appropriate changelog with a line for my changes.

Screenshots (if appropriate):

[krzysztof-causalens]

I think we could simply utilize the tag->component map like in the example here https://github.com/remarkjs/react-markdown?tab=readme-ov-file#use-custom-components-syntax-highlight rather than relying on our own regex?

[krzysztof-causalens]

Updated the approach slightly. Baked the code display into the base markdown display instead, if the code block has a specified language e.g. "```python...".
If no language is specified or it's an inline code block e.g. some code then default display is used.

@tamara-causalens let me know if this behaviour looks okay.

[krzysztof-causalens]

Dark mode doesn't look great in general yet but code blocks do switch to the opposite color which looks pretty good imo.

[tamara-causalens]

Looks amazing! 😍