### 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
case GLES3::CanvasShaderData::BLEND_MODE_LCD: {
					glBlendEquation(GL_FUNC_ADD);
					if (state.transparent_render_target) {
						glBlendFuncSeparate(GL_CONSTANT_COLOR, GL_ONE_MINUS_SRC_COLOR, GL_ONE, GL_ONE_MINUS_SRC_ALPHA);
					} else {
						glBlendFuncSeparate(GL_CONSTANT_COLOR, GL_ONE_MINUS_SRC_COLOR, GL_ZERO, GL_ONE);
					}
					glBlendColor(blend_color.r, blend_color.g, blend_color.b, blend_color.a);
				} break;
				case GLES3::CanvasShaderData::BLEND_MODE_MIX: {
					glBlendEquation(GL_FUNC_ADD);
					if (state.transparent_render_target) {
						glBlendFuncSeparate(GL_SRC_ALPHA, GL_ONE_MINUS_SRC_ALPHA, GL_ONE, GL_ONE_MINUS_SRC_ALPHA);
					} else {
						glBlendFuncSeparate(GL_SRC_ALPHA, GL_ONE_MINUS_SRC_ALPHA, GL_ZERO, GL_ONE);
					}
				} break;
				case GLES3::CanvasShaderData::BLEND_MODE_ADD: {
					glBlendEquation(GL_FUNC_ADD);
					if (state.transparent_render_target) {
						glBlendFuncSeparate(GL_SRC_ALPHA, GL_ONE, GL_SRC_ALPHA, GL_ONE);
					} else {
						glBlendFuncSeparate(GL_SRC_ALPHA, GL_ONE, GL_ZERO, GL_ONE);
					}
				} break;
				case GLES3::CanvasShaderData::BLEND_MODE_SUB: {
					glBlendEquation(GL_FUNC_REVERSE_SUBTRACT);
					if (state.transparent_render_target) {
						glBlendFuncSeparate(GL_SRC_ALPHA, GL_ONE, GL_SRC_ALPHA, GL_ONE);
					} else {