Fix GLTF/GLB importing by using append_from_file instead of buffers

[Davidweber01]

i got this error when trying to load a gltf as model in the new paint project menu:

ERROR: Condition "p_base_path.is_empty()" is true. Returning: ERR_INVALID_PARAMETER

at: _parse_buffers (modules/gltf/gltf_document.cpp:790)

ERROR: Condition "err != OK" is true. Returning: ERR_PARSE_ERROR

at: _parse_gltf_state (modules/gltf/gltf_document.cpp:6930)

ERROR: Condition "err != OK" is true. Returning: err

at: _parse (modules/gltf/gltf_document.cpp:6545)

ERROR: Condition "err != OK" is true. Returning: err

at: append_from_buffer (modules/gltf/gltf_document.cpp:7146)

Failure during parsing GLTF/GLB buffer

cause for the error was probably the empty string in this line:
var err = gltf.append_from_buffer(glb_filebytes, "", gltf_state)

so i changed it to use load_from_file instead, i dont see a reason why the file should first be converted to bytes instead of using the build in function