### Godot version

4.0 beta 17

### System information

Windows 11, Forward+, RTX 4090

### Issue description

In the latest beta, baking LightmapGI has taken a big performance hit. The baking itself might not be the problem, it's the (Re)Importing Assets step for the `.exr` that seems to take all the time.




### Steps to reproduce

I've included a repro project to demonstrate it. Click the `LightmapGI` node and then the `Bake Lightmaps` button.

Before Beta 17:
`Done baking lightmaps in 00:00:01.`

With Beta 17 (and the latest Master branch, just in case):
`Done baking lightmaps in 00:00:08.`



### Minimal reproduction project

[lightmap-regression-repro.zip](https://github.com/godotengine/godot/files/10579835/lightmap-regression-repro.zip)

}
		}
#endif
		LocalVector<BSPNode> bsp_nodes;
		LocalVector<int32_t> planes_tested;
		planes_tested.resize(bsp_planes.size());
		for (int &index : planes_tested) {
			index = 0x7FFFFFFF;
		}
		if (p_bake_step) {
			p_bake_step(0.9, RTR("Generating Probe Acceleration Structures"), p_bake_userdata, true);
		}
		_compute_bsp_tree(points, bsp_planes, planes_tested, bsp_simplices, bsp_simplex_indices, bsp_nodes);
		PackedInt32Array bsp_array;
		bsp_array.resize(bsp_nodes.size() * 6); 
		{
			float *fptr = (float *)bsp_array.ptrw();
			int32_t *iptr = (int32_t *)bsp_array.ptrw();
			for (uint32_t i = 0; i < bsp_nodes.size(); i++) {
				fptr[i * 6 + 0] = bsp_nodes[i].plane.normal.x;
				fptr[i * 6 + 1] = bsp_nodes[i].plane.normal.y;
				fptr[i * 6 + 2] = bsp_nodes[i].plane.normal.z;
				fptr[i * 6 + 3] = bsp_nodes[i].plane.d;
				iptr[i * 6 + 4] = bsp_nodes[i].over;
				iptr[i * 6 + 5] = bsp_nodes[i].under;
			}
#ifdef DEBUG_BSP_TREE
			Ref<FileAccess> f = FileAccess::open("res://bsp.txt", FileAccess::WRITE);
			for (uint32_t i = 0; i < bsp_nodes.size(); i++) {
				f->store_line(itos(i) + " - plane: " + bsp_nodes[i].plane + " over: " + itos(bsp_nodes[i].over) + " under: " + itos(bsp_nodes[i].under));