[docs] Rename callback and update migration guide

[m-bert]

Description

This PR does two things:

1. Renames onTouchesCancelled callback to onTouchesCancel
2. Adds few information to migration guide:
   2.1. Added information that onChange was removed
   2.2. Added information about removed state, oldState
   2.3. Added information about unified callback events types.

Test plan

Read docs 🤓

[j-piasecki]

Suggested change

	We decided to simplify API by removing `onChange` callback. You can now access `change*` properties in `onUpdate` callback.
	`onChange` callback has been removed, and its functionality integrated into `onUpdate`. You can now access `change*` properties in `onUpdate` callback.

[m-bert]

7d74133

[Copilot]

Pull request overview

This PR updates the documentation to reflect API changes in Gesture Handler 3, specifically renaming the onTouchesCancelled callback to onTouchesCancel and adding comprehensive migration guidance for removed features.

Changes:

• Renames onTouchesCancelled to onTouchesCancel across v3 documentation to match the v3 API implementation
• Adds migration guide sections explaining the removal of onChange callback, state/oldState properties, and the unification of event types

Reviewed changes

Copilot reviewed 4 out of 4 changed files in this pull request and generated 1 comment.

File	Description
packages/docs-gesture-handler/src/examples/CallbacksFlowCharts/TouchEventChart.jsx	Updates callback name in the touch event flow chart
packages/docs-gesture-handler/docs/guides/upgrading-to-3.mdx	Adds three new sections documenting removed onChange callback, removed state properties, and unified event types
packages/docs-gesture-handler/docs/gestures/use-manual-gesture.mdx	Updates callback reference in manual gesture tutorial
packages/docs-gesture-handler/docs/fundamentals/callbacks-events.mdx	Updates callback name and signature in API reference

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[m-bert]

I've also noticed that I have not added onTouchesCancel change into "Renamed callbacks" section. Done in ceff49c