fix(datasetattributes): Fix active attribute assignment

[sankhesh]

This change fixes an issue where setting different attributes after initializing the dataset causes the active attributes to be retained from previous dataset state.

Context

When dynamically changing TubeFilter properties at runtime, tubes with colormaps lose their colors and render as solid.

Steps to Reproduce

1. Open the official TubeFilter example: https://kitware.github.io/vtk-js/examples/TubeFilter.html
2. Observe the initial tubes with proper colormap (red and yellow tubes) ✅
3. Modify any tube property using the controls (Number of Sides, Radius, etc.) ❌
4. Bug: Tubes lose their colors and become solid white/gray

Results

Changes

• Documentation and TypeScript definitions were updated to match those changes

PR and Code Checklist

• semantic-release commit messages
• Run npm run reformat to have correctly formatted code

Testing

• This change adds or fixes unit tests
• Tested environment:
  • vtk.js:
  • OS:
  • Browser:

[finetjul]

LGTM.
Did you check that your dataset does not get bigger and bigger because new arrays get added without being removed when properties are changed ?