Enhance Markdown rendering with tables and inline code support

[ritwikshanker]

This pull request enhances the Markdown rendering capabilities of the MessageMarkdown component to better support tables and additional Markdown features. Tables are now displayed as proper HTML tables with correct alignment and cell handling, and Markdown elements such as italics, inline code, and headings are rendered without exposing their raw markers. The changes also include comprehensive tests for these new features.

Markdown rendering improvements:

• Tables written in Markdown (with header, delimiter, and body rows) are now rendered as real HTML tables with proper column alignment and cell padding, instead of as plain text with pipes. Ragged rows are padded to maintain column structure. [1] [2] [3]
• Italics (*italic*), inline code (`code`), and headings (## Heading) are rendered with appropriate HTML tags and styling, and their Markdown markers are no longer shown in the output. [1] [2] [3]

Testing enhancements:

• Added comprehensive tests to verify correct rendering of tables, italics, code, and headings, as well as edge cases such as ragged rows and lone pipe lines.

Documentation updates:

• Updated CHANGELOG.md to document the improved table rendering and Markdown element handling.