Reset state.isDraggingInternally using global event handlers

[12joan]

Description
Listen for dragend and drop events globally to reset state.isDraggingInternally. In Firefox, if a drop handler initiates an operation that causes the originally dragged element to unmount, that element will not emit a dragend event.

Issue
Fixes: #5663

Example
See issue

Context
We may want to remove the React onDragEnd handler, since after this change, all it does is delegate the event if certain conditions are met.

Checks

• The new code matches the existing patterns and styles.
• The tests pass with yarn test.
• The linter passes with yarn lint. (Fix errors with yarn fix.)
• The relevant examples still work. (Run examples with yarn start.)
• You've added a changeset if changing functionality. (Add one with yarn changeset add.)

[changeset-bot]

🦋 Changeset detected

Latest commit: 89b250a

The changes in this PR will be included in the next version bump.

This PR includes changesets to release 1 package

Name	Type
slate-react	Patch

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