Centralize and Refactor Photo Filtering with combineLatest

[amujalo2]

Goal:
Use reactive composition to dynamically filter photos based on selected tags and approval
status.
Details:

1. In the photo list component, combine observables:
   • selected tags
   • approval status
   • photo stream
2. Use combineLatest and map to transform the filtered photo list.
3. Ensure filtering reacts immediately to UI changes