### Godot version

4.1.1.stable, 4.2.dev (2282fc5de)

### System information

Arch Linux - X11 - GLES3 (Compatibility) - NVIDIA GeForce RTX 3060 Ti (nvidia; 535.104.05) - 13th Gen Intel(R) Core(TM) i5-13400F (16 Threads)

### Issue description

When using Compatibility renderer, adjusting the Alpha component of clear color affects 2D editor content.

This does not happen when using Forward+ or Mobile renderer. Does not affect 3D editor and the running game.


https://github.com/godotengine/godot/assets/372476/e398522e-590a-4832-959f-ea8ba8e71c5d



### Steps to reproduce

1. Create a project using Compatibility renderer.
2. Adjust the clear color's alpha component in Project Settings.

### Minimal reproduction project

N/A
PolygonBuffers pb;
	glGenBuffers(1, &pb.vertex_buffer);
	glGenVertexArrays(1, &pb.vertex_array);
	glBindVertexArray(pb.vertex_array);
	pb.count = vertex_count;
	pb.index_buffer = 0;
	uint32_t buffer_size = stride * p_points.size();
	Vector<uint8_t> polygon_buffer;
	polygon_buffer.resize(buffer_size * sizeof(float));
	{
		glBindBuffer(GL_ARRAY_BUFFER, pb.vertex_buffer);
		uint8_t *r = polygon_buffer.ptrw();
		float *fptr = reinterpret_cast<float *>(r);
		uint32_t *uptr = (uint32_t *)r;
		uint32_t base_offset = 0;
		{
			
			glEnableVertexAttribArray(RS::ARRAY_VERTEX);
			glVertexAttribPointer(RS::ARRAY_VERTEX, 2, GL_FLOAT, GL_FALSE, stride * sizeof(float), nullptr);
			const Vector2 *points_ptr = p_points.ptr();
			for (uint32_t i = 0; i < vertex_count; i++) {
				fptr[base_offset + i * stride + 0] = points_ptr[i].x;
				fptr[base_offset + i * stride + 1] = points_ptr[i].y;
			}
			base_offset += 2;
		}
		
		if ((uint32_t)p_colors.size() == vertex_count) {
			glEnableVertexAttribArray(RS::ARRAY_COLOR);
			glVertexAttribPointer(RS::ARRAY_COLOR, 4, GL_FLOAT, GL_FALSE, stride * sizeof(float), CAST_INT_TO_UCHAR_PTR(base_offset * sizeof(float)));