feat(pydeck): add mapId support for Google Maps

[n0531m]

This PR adds support for the mapId parameter when using Google Maps as a basemap provider in pydeck.

Specifying a mapId is required to enable Google Maps Vector Maps, which unlocks modern features such as:

• 3D Perspective: Enables synchronized 3D tilt and rotation between the base map and deck.gl layers.
• Vector Rendering: Provides smoother zooming and better performance for large datasets.
• Custom Styling: Allows users to use Cloud-based Map Styling via the Google Maps Platform console.

This change includes updates to both the Python bindings (pydeck) and the JavaScript component (@deck.gl/jupyter-widget) to ensure seamless
synchronization in Jupyter environments, standalone HTML exports, and Google Colab.

Changes

Python (pydeck)

• pydeck.Deck: Added google_maps_map_id support to the constructor (via api_keys dict) and automatic environment variable detection for
  GOOGLE_MAPS_MAP_ID.
• pydeck.widget.DeckGLWidget: Added the google_maps_map_id traitlet to enable state synchronization between Python and the Jupyter frontend.
• HTML Templates: Updated the Jinja2 template to propagate the Map ID to the createDeck initialization call.
• Documentation: Updated docstrings for Deck and DeckGLWidget to include information on using Map IDs.

JavaScript (@deck.gl/jupyter-widget)

• Model: Added google_maps_map_id to the Jupyter widget model defaults.
• Map Initialization: Updated the Google Maps initialization utility to pass mapId to the google.maps.Map constructor.
• Robustness: Ensured mapId is a truly optional parameter; it is only added to the map options if a valid ID is provided.

Example Usage

   import pydeck
   import os

   # Set environment variables or pass via api_keys
   os.environ["GOOGLE_MAPS_API_KEY"] = "YOUR_KEY"
   os.environ["GOOGLE_MAPS_MAP_ID"] = "YOUR_VECTOR_MAP_ID"

   view_state = pydeck.ViewState(
       latitude=37.7749, 
       longitude=-122.4194, 
       zoom=12, 
       pitch=45  # Now tilts the base map too!
   )

   deck = pydeck.Deck(
       map_provider="google_maps",
       initial_view_state=view_state
   )
   deck.show()

Testing Performed

• Logic Verification: Confirmed Deck object correctly captures IDs from both constructor and environment variables.
• Serialization Verification: Verified that google_maps_map_id is correctly excluded from the layer JSON to keep the configuration at the
  provider level.
• HTML Export Verification: Confirmed that to_html() correctly generates the googleMapsMapId property in the frontend createDeck call.
• Widget Verification: Confirmed traits are correctly synchronized between Python and the frontend model.

Related Issues
Enables official support for Google Maps Vector Maps, resolving gaps highlighted in several community issues (e.g., #9856, #8476) where users previously had to use manual workarounds to synchronize mapId.