fix(ui): allow XML tag for markdown rich input (#6095)

* fix(ui): allow XML tag for rich input

- Introduced utilities for escaping and unescaping non-standard XML/HTML tags to preserve them during markdown processing.
- Updated RichInput and ExpandRichInputDialog components to utilize the new XML tag utilities for handling custom tags.
- Added Jest configuration for the UI package and created tests for the XML tag utilities to ensure functionality.
- Updated package.json to include Jest as a dependency and added a test script.

* address code review comments from Gemini

* allow html tag in markdown editor

* add test case for markdown format

* update dependency in ui