Use UV for image texture with no tex coord input

Previously when no texture coordinate input for ImageTexture, always
defaults to Blender Generated Coordinates. However, it is not consistent
with Blender's behaviour, which defaults use UV.

io_scene_godot/converters/material/script_shader/node_converters.py

@@ -760,9 +760,7 @@ class ImageTextureNodeConverter(NodeConverterBase):
         tex_coord_socket = self.bl_node.inputs[0]
         tex_coord = self.in_sockets_map[tex_coord_socket]
         if not tex_coord_socket.is_linked:
-            # default to use generated texture coordinates
-            self.flags.aabb_tex_coord_used = True
-            self.local_code.append("%s = %s" % (tex_coord, self.AABB_UVW))
+            self.local_code.append("%s = vec3（UV, 0.0）" % tex_coord)
 
         tex_var = self.generate_tmp_texture_id(self.bl_node.name)
         if self.bl_node.image is not None: