remove duplicate UploadMeshData calls on the same mesh

[apilatosba]

good morning. In all changed files, after LoadOBJ() is called, UploadMeshData() is called on the returned mesh:

    // LESSON 04: Load 3d model
    Mesh mesh = LoadOBJ("resources/dwarf.obj");     // Load mesh data from OBJ file
    UploadMeshData(&mesh);                          // Upload mesh data to GPU memory (VRAM)

but UploadMeshData() is also called inside the LoadOBJ() function right before return statement:

    // Upload mesh data into VRAM
    UploadMeshData(&mesh);

    return mesh;

so UploadMeshData() is unnecessary in LoadOBJ() function. or vice versa, we should keep UploadMeshData() in LoadOBJ() and remove the others.