Document missing component props

[mintlify-development]

Summary

• Added disabled prop documentation to Card component
• Added onChange and lazy prop documentation to Expandable component
• Added formal Properties section with dropdown prop to CodeGroup component

These props exist in the client source code but were missing from the documentation.

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Note

Low Risk
Documentation-only updates that add missing prop descriptions; no runtime or behavioral code changes.

Overview
Adds missing component prop documentation across the MDX docs: Card now documents a disabled prop to disable link/CTA interaction.

CodeGroup gains a formal Properties section documenting the dropdown boolean, and Expandable documents new onChange and lazy props (plus a small punctuation fix in defaultOpen).

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