Bump @types/leaflet from 1.9.20 to 1.9.21

Bump @types/leaflet from 1.9.20 to 1.9.21

Bumps [@types/leaflet](https://github.com/DefinitelyTyped/DefinitelyTyped/tree/HEAD/types/leaflet) from 1.9.20 to 1.9.21.
- [Release notes](https://github.com/DefinitelyTyped/DefinitelyTyped/releases)
- [Commits](https://github.com/DefinitelyTyped/DefinitelyTyped/commits/HEAD/types/leaflet)

---
updated-dependencies:
- dependency-name: "@types/leaflet"
  dependency-version: 1.9.21
  dependency-type: direct:development
  update-type: version-update:semver-patch
...

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