### Tested versions

Godot Engine v4.2.stable.official.46dc27791

### System information

Windows 10

### Issue description

When exporting to web, Godot fails with this error in the console:

> scene/main/window.cpp:884 - Attempting to make child window exclusive, but the parent window already has another exclusive child. This window: /root/@<!-- -->EditorNode@<!-- -->17120/@<!-- -->Panel@<!-- -->13/@<!-- -->ProjectExportDialog@<!-- -->559/@<!-- -->VBoxContainer@<!-- -->137/@<!-- -->AcceptDialog@<!-- -->411, parent window: /root/@<!-- -->EditorNode@<!-- -->17120/@<!-- -->Panel@<!-- -->13/@<!-- -->ProjectExportDialog@<!-- -->559, current exclusive child window: /root/@<!-- -->EditorNode@<!-- -->17120/@<!-- -->Panel@<!-- -->13/@<!-- -->ProjectExportDialog@<!-- -->559/@<!-- -->ProgressDialog@<!-- -->17444

![a](https://github.com/godotengine/godot/assets/2000051/bf9d22aa-d3fe-4e11-bff6-c387e740fe90)

This happens for newly created empty projects.


### Steps to reproduce

1. Open the attached project (or create a new project).
2. Project->Export->Export All
3. Observe the console error.  No output files are generated.


### Minimal reproduction project (MRP)

[export_test.zip](https://github.com/godotengine/godot/files/13574810/export_test.zip)

len += 8;
				len = BSWAP32(len);
				memcpy(&data.write[ofs], icon_infos[i].name, 4);
				encode_uint32(len, &data.write[ofs + 4]);
			
		 else {
			Vector<uint8_t> src_data = copy->get_data();
			// Encode 24-bit RGB RLE icon.
			{
				int ofs = data.size();
				data.resize(data.size() + 8);
				o_packbits_encode(0, icon_infos[i].size, src_data, data); // Encode R.
				o_packbits_encode(1, icon_infos[i].size, src_data, data); // Encode G.
				o_packbits_encode(2, icon_infos[i].size, src_data, data); // Encode B.
				 = data.size() - ofs;
				len = BSWAP32(len);
				memcpy(&data.write[ofs], icon_infos[i].name, 4);
				encode_uint32(len, &data.write[ofs + 4]);
			
			// Encode 8-bit mask uncompressed icon.
			{
				int ofs = data.size();
				 = copy->get_width() * copy->get_height();
				data.resize(data.size() + len + 8);
				for (int j = 0; j < len; j++) {
					data.write[ofs + 8 + j] = src_data.ptr()[j * 4 + 3];
				
				len += 8;
				len = BSWAP32(len);
				memcpy(&data.write[ofs], icon_infos[i].mask_name, 4);