[cpruijsen]

Title: fix(InteractorStyleImage): stop mouse move slicing during wheel

### Context

Fixes #3642.

This removes the wheel start/end overrides from `vtkInteractorStyleImage`, so a mouse move during a wheel gesture no longer changes the camera distance.

`handleStartMouseWheel` called `startSlice()` and `handleEndMouseWheel` called `endSlice()`, so `model.state` stayed `IS_SLICE` for the whole gesture, including the wheel-end debounce window. `handleMouseMove` then sent each pointer move to `slice()`, which calls `camera.setDistance`. As discussed in the issue, `startSlice()`/`endSlice()` should only be used for the ctrl + left button interaction.

### Results

The new test `Sources/Interaction/Style/InteractorStyleImage/test/testMouseWheel.js` runs start wheel, mouse move, end wheel and checks that the camera distance and focal point do not change. It fails without the fix (distance 3.2036 becomes 3.2994) and passes with it.

### Changes

- `Sources/Interaction/Style/InteractorStyleImage/index.js`: removed the `handleStartMouseWheel` and `handleEndMouseWheel` overrides. The style now inherits them from `vtkInteractorStyleTrackballCamera`, which sets `wheelDolly` and ignores pointer movement while it is set. `endDolly()` still renders at the end of the gesture.
- Ctrl + left button slicing and `handleMouseWheel` (camera distance and reslice plane scroll) are unchanged.
- Event change: a wheel gesture now fires `StartDollyEvent`/`EndDollyEvent`, the same as `vtkInteractorStyleTrackballCamera`, and no longer fires `StartSliceEvent`/`EndSliceEvent`. `StartInteractionEvent`/`EndInteractionEvent` still fire.
- No API or TypeScript change: both methods still exist through inheritance.

Empty overrides would also fix the bug, but they would drop the render at the end of the gesture. I can switch to that if you prefer.

### PR Checklist

- [ ] GitHub Actions CI passed: semantic-release commit messages, lint, and tests
- [x] Test coverage added
- [x] Documentation and TypeScript definitions are updated to match these changes (no API change)