fix(examples): fix the stack and volume segmentation adapters example (…

…#1680)

* fix

* refactor(segmentation): streamline segmentation handling and improve toolbar functionality

- Consolidated segmentation-related functions into a new utils module for better organization.
- Updated toolbar buttons to utilize the new state management for DICOM and SEG file handling.
- Enhanced user instructions for loading and exporting segmentation data.
- Introduced a toggle for handling overlapping segments during segmentation loading.
- Improved event handling for file selection and drag-and-drop functionality.
- Refactored rendering engine and viewport setup for clarity and maintainability.