Match NavMap and ProjectSettings with NavigationMesh defaults

Match NavMap and ProjectSettings with NavigationMesh defaults since the NavMap edge merging requires a matching cell_size with the NavigationMesh to create connections without issues.

doc/classes/ProjectSettings.xml

@@ -1375,10 +1375,10 @@
 		<member name="navigation/2d/default_edge_connection_margin" type="int" setter="" getter="" default="1">
 			Default edge connection margin for 2D navigation maps. See [method NavigationServer2D.map_set_edge_connection_margin].
 		</member>
-		<member name="navigation/3d/default_cell_size" type="float" setter="" getter="" default="0.3">
+		<member name="navigation/3d/default_cell_size" type="float" setter="" getter="" default="0.25">
 			Default cell size for 3D navigation maps. See [method NavigationServer3D.map_set_cell_size].
 		</member>
-		<member name="navigation/3d/default_edge_connection_margin" type="float" setter="" getter="" default="0.3">
+		<member name="navigation/3d/default_edge_connection_margin" type="float" setter="" getter="" default="0.25">
 			Default edge connection margin for 3D navigation maps. See [method NavigationServer3D.map_set_edge_connection_margin].
 		</member>
 		<member name="network/limits/debugger/max_chars_per_second" type="int" setter="" getter="" default="32768">

modules/navigation/nav_map.h

@@ -50,10 +50,10 @@ class NavMap : public NavRid {
 
 	/// To find the polygons edges the vertices are displaced in a grid where
 	/// each cell has the following cell_size.
-	real_t cell_size = 0.3;
+	real_t cell_size = 0.25;
 
 	/// This value is used to detect the near edges to connect.
-	real_t edge_connection_margin = 5.0;
+	real_t edge_connection_margin = 0.25;
 
 	bool regenerate_polygons = true;
 	bool regenerate_links = true;

scene/resources/world_3d.cpp

@@ -150,8 +150,8 @@ World3D::World3D() {
 
 	navigation_map = NavigationServer3D::get_singleton()->map_create();
 	NavigationServer3D::get_singleton()->map_set_active(navigation_map, true);
-	NavigationServer3D::get_singleton()->map_set_cell_size(navigation_map, GLOBAL_DEF("navigation/3d/default_cell_size", 0.3));
-	NavigationServer3D::get_singleton()->map_set_edge_connection_margin(navigation_map, GLOBAL_DEF("navigation/3d/default_edge_connection_margin", 0.3));
+	NavigationServer3D::get_singleton()->map_set_cell_size(navigation_map, GLOBAL_DEF("navigation/3d/default_cell_size", 0.25));
+	NavigationServer3D::get_singleton()->map_set_edge_connection_margin(navigation_map, GLOBAL_DEF("navigation/3d/default_edge_connection_margin", 0.25));
 }
 
 World3D::~World3D() {