### 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
const Color *color_ptr = p_colors.ptr();
			for (uint32_t i = 0; i < vertex_count; i++) {
				fptr[base_offset + i * stride + 0] = color_ptr[i].r;
				fptr[base_offset + i * stride + 1] = color_ptr[i].g;
				fptr[base_offset + i * stride + 2] = color_ptr[i].b;
				fptr[base_offset + i * stride + 3] = color_ptr[i].a;
			}
			base_offset += 4;
		} else {
			glDisableVertexAttribArray(RS::ARRAY_COLOR);
			pb.color_disabled = true;
			pb.color = p_colors.size() == 1 ? p_colors[0] : Color(1.0, 1.0, 1.0, 1.0);
		}
		if ((uint32_t)p_uvs.size() == vertex_count) {
			glEnableVertexAttribArray(RS::ARRAY_TEX_UV);
			glVertexAttribPointer(RS::ARRAY_TEX_UV, 2, GL_FLOAT, GL_FALSE, stride * sizeof(float), CAST_INT_TO_UCHAR_PTR(base_offset * sizeof(float)));
			const Vector2 *uv_ptr = p_uvs.ptr();
			for (uint32_t i = 0; i < vertex_count; i++) {
				fptr[base_offset + i * stride + 0] = uv_ptr[i].x;
				fptr[base_offset + i * stride + 1] = uv_ptr[i].y;
			}
			base_offset += 2;
		} else {
			glDisableVertexAttribArray(RS::ARRAY_TEX_UV);
		}
		if ((uint32_t)p_indices.size() == vertex_count * 4 && (uint32_t)p_weights.size() == vertex_count * 4) {
			glEnableVertexAttribArray(RS::ARRAY_BONES);
			glVertexAttribPointer(RS::ARRAY_BONES, 4, GL_UNSIGNED_INT, GL_FALSE, stride * sizeof(float), CAST_INT_TO_UCHAR_PTR(base_offset * sizeof(float)));
			const int *bone_ptr = p_bones.ptr();
			for (uint32_t i = 0; i < vertex_count; i++) {