### 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
uint16_t *bone16w = (uint16_t *)&uptr[base_offset + i * stride];
				bone16w[0] = bone_ptr[i * 4 + 0];
				bone16w[1] = bone_ptr[i * 4 + 1];
				bone16w[2] = bone_ptr[i * 4 + 2];
				bone16w[3] = bone_ptr[i * 4 + 3];
			}
			base_offset += 2;
		} else {
			glDisableVertexAttribArray(RS::ARRAY_BONES);
		}
		if ((uint32_t)p_weights.size() == vertex_count * 4) {
			glEnableVertexAttribArray(RS::ARRAY_WEIGHTS);
			glVertexAttribPointer(RS::ARRAY_WEIGHTS, 4, GL_FLOAT, GL_FALSE, stride * sizeof(float), CAST_INT_TO_UCHAR_PTR(base_offset * sizeof(float)));
			const float *weight_ptr = p_weights.ptr();
			for (uint32_t i = 0; i < vertex_count; i++) {
				uint16_t *weight16w = (uint16_t *)&uptr[base_offset + i * stride];
				weight16w[0] = CLAMP(weight_ptr[i * 4 + 0] * 65535, 0, 65535);
				weight16w[1] = CLAMP(weight_ptr[i * 4 + 1] * 65535, 0, 65535);
				weight16w[2] = CLAMP(weight_ptr[i * 4 + 2] * 65535, 0, 65535);
				weight16w[3] = CLAMP(weight_ptr[i * 4 + 3] * 65535, 0, 65535);
			}
			base_offset += 2;
		} else {
			glDisableVertexAttribArray(RS::ARRAY_WEIGHTS);
		}
		ERR_FAIL_COND_V(base_offset != stride, 0);
		GLES3::Utilities::get_singleton()->buffer_allocate_data(GL_ARRAY_BUFFER, pb.vertex_buffer, vertex_count * stride * sizeof(float), polygon_buffer.ptr(), GL_STATIC_DRAW, "Polygon 2D vertex buffer");
	}
	if (p_indices.size()) {