Don't trigger pointer move on zoom (#3305)

In this PR, when the camera changes, we check whether the pointer's page
position has actually changed before triggering a pointer move event.
This means that the pointer move will not fire while zooming in and out.

### Change Type

- [x] `sdk` — Changes the tldraw SDK
- [x] `improvement` — Improving existing features

### Test Plan

1. Zoom in and out.
2. The performance tab should not see any calls to `updateHoveredShape`
or other pointer move related events.

### Release Notes

- Improve performance of zooming.

packages/editor/src/lib/editor/Editor.ts

@@ -2093,13 +2093,20 @@ export class Editor extends EventEmitter<TLEventMap> {
 		}
 
 		this.batch(() => {
-			this.store.put([{ ...currentCamera, ...point }]) // include id and meta here
+			const camera = { ...currentCamera, ...point }
+			this.store.put([camera]) // include id and meta here
 
 			// Dispatch a new pointer move because the pointer's page will have changed
 			// (its screen position will compute to a new page position given the new camera position)
-			const { currentScreenPoint } = this.inputs
+			const { currentScreenPoint, currentPagePoint } = this.inputs
 			const { screenBounds } = this.store.unsafeGetWithoutCapture(TLINSTANCE_ID)!
 
+			// compare the next page point (derived from the curent camera) to the current page point
+			if (
+				currentScreenPoint.x / camera.z - camera.x !== currentPagePoint.x ||
+				currentScreenPoint.y / camera.z - camera.y !== currentPagePoint.y
+			) {
+				// If it's changed, dispatch a pointer event
 				this.dispatch({
 					type: 'pointer',
 					target: 'canvas',
@@ -2113,6 +2120,7 @@ export class Editor extends EventEmitter<TLEventMap> {
 					button: 0,
 					isPen: this.getInstanceState().isPenMode ?? false,
 				})
+			}
 
 			this._tickCameraState()
 		})