comp: Only use dedicated allocation when supported/preferred
This fixes an issue observed on tegra where depth textures are required to not use dedicated allocation.
The decisive lines here are
GLint dedicated = xscn->images[i].use_dedicated_allocation ? GL_TRUE : GL_FALSE; glMemoryObjectParameterivEXT(sc->memory[i], GL_DEDICATED_MEMORY_OBJECT_EXT, &dedicated);
because it was observed that importing the vulkan texture with the wrong dedicated/not dedicated model would cause OpenGL depth attachment to not work / be corrupted and break all rendering that uses depth testing.