Bump hono from 4.11.4 to 4.12.12 in /samples/Whiteboard/MCPServer

Bumps [hono](https://github.com/honojs/hono) from 4.11.4 to 4.12.12.
- [Release notes](https://github.com/honojs/hono/releases)
- [Commits](honojs/hono@v4.11.4...v4.12.12)

---
updated-dependencies:
- dependency-name: hono
  dependency-version: 4.12.12
  dependency-type: indirect
...

Signed-off-by: dependabot[bot] <[email protected]>

Author: dependabot[bot]