Crash when Renderer::AddMesh() is called on empty mesh

[MrDmitry]

Mesh has VerticesUpdated signal that is listened by VkMesh however when you create a fresh mesh and try to add it to the Renderer you get a crash here:

void VkMesh::AllocateOnGPU()
{
    m_vertexBuffer.Destroy();
    m_indexBuffer.Destroy();
    Buffer stagingBuffer;
    //Vertexes filling
    auto size = sizeof(m_mesh.GetVertices()[0]) * m_mesh.GetVertices().size();
    stagingBuffer.Create(m_physicalDevice, m_device, vk::BufferUsageFlagBits::eTransferSrc, vk::MemoryPropertyFlagBits::eHostVisible | vk::MemoryPropertyFlagBits::eHostCoherent, size);
    m_vertexBuffer.Create(m_physicalDevice, m_device, vk::BufferUsageFlagBits::eVertexBuffer | vk::BufferUsageFlagBits::eTransferDst, vk::MemoryPropertyFlagBits::eDeviceLocal, size);

    stagingBuffer.Map();
<crash>

stagingBuffer.Create leads to an error LOG_ERROR("Can't allocate zero Vulkan buffer on gpu!"); and returns false but this return value is never checked

Also consider a case where mesh is updated with 0 vertices, this should also be properly handled (old information shall be freed)