Notebook unit testing

Notion task: https://www.notion.so/qim-dtu/Unit-test-for-notebooks-184bab83b2f980df8b99ebb8c4386c83

• Updated the notebooks to comply with the refactoring changes.
• Implemented unit tests for all notebooks (except annotation_tool.ipynb, segmentation_pipeline.ipynb, and Unet.ipynb). The unit tests are located in qim3d/tests/notebooks/test_notebooks.py.

qim3d/tests/notebooks/test_filters.py

+from testbook import testbook
+
+def test_filters_notebook():
+    with testbook('./docs/notebooks/filters.ipynb', execute=True) as tb:
+        pass
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