[New Rich Text Editor]: implement remove all formatting button

[habibayman]

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Desired behavior

This was newly added to the design.
The new editions to the component should:

• Add a new button to support “removing all formatting” from a node
• Maintain existing support for:
  • Text styling (bold, italic, underline, strikethrough), list formatting (unordered, ordered), headings (small, normal, h1–h3), undo/redo, copy/paste (with formatting options), keyboard navigation (including tab traversal), RTL language support, and internationalization (i18n)
• Match the planned design

Current behavior

• TipTap and core formatting features are already implemented
• Component is available for isolated development at http://localhost:8080/editor-dev#/
• New docs file (e.g. docs/rich_text_editor.md) is updated with component integration notes
• The insertion buttons listed above are not yet added or functional

Value add

The completion for this is essential for a good UX

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Add labels

• dependencies
• DEV: frontend