Fix noise extent and memory leak in vtkImageDataLIC2D
vtkImageDataLIC2D tried to copy 2 float components of its noise texture to the GPU memory, though only one component is generated and used.
Regarding the magnification shader in vtkImageDataLIC2D in the old rendering backend:
- it was not deleted in the destructor.
- if the shader did not build successfully: it was not deleted and mistakenly accessed