chore(package.json): remove redundant react-dnd dependency

[benatshippabo]

Issue

If left alone, it causes a headache when trying to meet the peer dependency ^7.3.0 when it doesn't reflect the actual version being used by react-sortable-tree. Juggling with @types/react-sortable-tree there are three separate react-dnd version requirements. And having multiple version of react-dnd will lead to runtime errors.

Fix

Removed react-dnd from peerDependencies since we already declared react-dnd as a normal dependency 🤔