fix: export WebGLEarth classes from plugins __init__.py (fixes docs build)

Author: Kakarot35

folium/plugins/__init__.py

@@ -37,6 +37,7 @@
 from folium.plugins.timestamped_wmstilelayer import TimestampedWmsTileLayers
 from folium.plugins.treelayercontrol import TreeLayerControl
 from folium.plugins.vectorgrid_protobuf import VectorGridProtobuf
+from folium.plugins.webgl_earth import WebGLEarth, WebGLEarthMarker, WebGLEarthTileLayer, WebGLEarthRealtime
 
 __all__ = [
     "AntPath",
@@ -79,4 +80,8 @@
     "TimestampedWmsTileLayers",
     "TreeLayerControl",
     "VectorGridProtobuf",
+    "WebGLEarth",
+    "WebGLEarthMarker",
+    "WebGLEarthTileLayer",
+    "WebGLEarthRealtime",
 ]