### 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)

w_albedo[i + 2] = uint8_t(CLAMP(float(r_aa[i + 2]) * (1.0 - float(r_orm[i + 2] / 255.0)), 0, 255));
					w_albedo[i + 3] = 255;
				}
				md.albedo_on_uv2.instantiate();
				md.albedo_on_uv2->set_data(lightmap_size.width, lightmap_size.height, false, Image::FORMAT_RGBA8, albedom);
			}
			md.emission_on_uv2 = images[RS::BAKE_CHANNEL_EMISSION];
			if (md.emission_on_uv2->get_format() != Image::FORMAT_RGBAH) {
				md.emission_on_uv2->convert(Image::FORMAT_RGBAH);
			}
			
			Basis normal_xform = mf.xform.basis.inverse().transposed();
			for (int i = 0; i < mf.mesh->get_surface_count(); i++) {
				if (mf.mesh->surface_get_primitive_type(i) != Mesh::PRIMITIVE_TRIANGLES) {
					continue;
				}
				Array a = mf.mesh->surface_get_arrays(i);
				Vector<Vector3> vertices = a[Mesh::ARRAY_VERTEX];
				const Vector3 *vr = vertices.ptr();
				Vector<Vector2> uv = a[Mesh::ARRAY_TEX_UV2];
				const Vector2 *uvr = nullptr;
				Vector<Vector3> normals = a[Mesh::ARRAY_NORMAL];
				const Vector3 *nr = nullptr;
				Vector<int> index = a[Mesh::ARRAY_INDEX];
				ERR_CONTINUE(uv.size() == 0);
				ERR_CONTINUE(normals.size() == 0);
				uvr = uv.ptr();
				nr = normals.ptr();
				int facecount;
				const int *ir = nullptr;