### 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)

mesh_data.push_back(md);
		}
	}
	
	if (p_bake_step) {
		p_bake_step(0.3, RTR("Creating probes"), p_bake_userdata, true);
	}
	
	for (int i = 0; i < probes_found.size(); i++) {
		bounds.expand_to(probes_found[i]);
	}
	bounds.grow_by(bounds.size.length() * 0.001);
	if (gen_probes == GENERATE_PROBES_DISABLED) {
		
		for (int i = 0; i < 8; i++) {
			probes_found.push_back(bounds.get_endpoint(i));
		}
	} else {
		
		static const int subdiv_values[6] = { 0, 4, 8, 16, 32 };
		int subdiv = subdiv_values[gen_probes];
		float subdiv_cell_size;
		Vector3i bound_limit;
		{
			int longest_axis = bounds.get_longest_axis_index();
			subdiv_cell_size = bounds.size[longest_axis] / subdiv;
			int axis_n1 = (longest_axis + 1) % 3;
			int axis_n2 = (longest_axis + 2) % 3;
			bound_limit[longest_axis] = subdiv;
			bound_limit[axis_n1] = int(Math::ceil(bounds.size[axis_n1] / subdiv_cell_size));