This PR adds pre-checks when enabling validation layers.
For validation layers to work some platforms require that
the Vulkan SDK is installed. Validation layers are activated
when running blender with `--debug-gpu`.
Sometimes we expect users to run with `--debug-gpu` for
narrowing down an issue and we cannot expect them to have
the Vulkan SDK installed.
This patch will check if the `VK_LAYER_PATH` is available
and that the configuration file of the validation layer is
present. If this isn't the case we don't activate the
requested validation layer.
Pull Request: https://projects.blender.org/blender/blender/pulls/105922
a64877f045