🐛 Bug report | Transparency applied globally when toggling heat maps

[stevenlabelle]

Description:
If one material is assigned transparency < 1 and then heat maps are toggled on, all materials will be given that new transparency. Hiding the semi-transparent material and toggling heat maps restores the opacity of the other materials.

Version:
Dev Version 3.0.0.b1703c4b1

Steps To Reproduce:

1. Open a model on the post side
2. Change one of the material's opacity to 0.1
3. Enable a heatmap variable from the top (e.g., 1st principal strain). All materials will become transparent.
4. Toggle the visibility of the semi-transparent material.
5. Toggle the heat map off then on to see only the opaque materials.
6. Toggle the visibility of the semi-transparent material. It now appears as fully opaque.