fix(Rendering): fix an issue with textures of short/int
fix(Rendering): fix an issue with textures of short/int

There was a mismatch in the code for Webgl2 that caused
issues when using data types other than float/uchar in
textures

Kitware/vtk-js,Kitware/vtk-js,Kitware/vtk-js,Kitware/vtk-js