feat: Enable Full Dataset Support & Improve Documentation

[henrikvalv3]

Summary
This PR updates the places_insights_sample_data_demo.ipynb notebook to support customers using both Sample & Full Data. It also enhances the in-notebook documentation to better explain the geospatial SQL logic and visualization techniques.

Key Changes

• Configuration (Cell 2): Added a DATASET_MODE dropdown that allows users to toggle between "Sample Data" and "Full Data." The notebook now automatically constructs the correct table names (e.g., ___sample.places_sample vs .places) based on this selection.
• Documentation:
  • Updated the Introduction to reflect the notebook's dual purpose (Sample vs. Full).
  • Added direct links to Cloud Setup documentation for both subscription types.
  • Clarified the usage of the CUSTOM_TABLE_NAME override field.
  • Rewrote the headers for Cells 4, 5, 6, and 7 to provide a step-by-step breakdown of the "Radius Search" vs. "H3 Grid Search" workflows, explaining the specific SQL functions (ST_DWITHIN, PLACES_COUNT_PER_H3) and visualization layers used.
• Error Handling: Added hints to query error messages suggesting users verify their specific Analytics Hub subscriptions.