### 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
GLuint new_buffers[3];
	glGenBuffers(3, new_buffers);
	
	glBindBuffer(GL_ARRAY_BUFFER, new_buffers[0]);
	GLES3::Utilities::get_singleton()->buffer_allocate_data(GL_ARRAY_BUFFER, new_buffers[0], data.max_instance_buffer_size, nullptr, GL_STREAM_DRAW, "2D Batch UBO[" + itos(state.current_data_buffer_index) + "][0]");
	
	glBindBuffer(GL_UNIFORM_BUFFER, new_buffers[1]);
	GLES3::Utilities::get_singleton()->buffer_allocate_data(GL_UNIFORM_BUFFER, new_buffers[1], sizeof(LightUniform) * data.max_lights_per_render, nullptr, GL_STREAM_DRAW, "2D Lights UBO[" + itos(state.current_data_buffer_index) + "]");
	
	glBindBuffer(GL_UNIFORM_BUFFER, new_buffers[2]);
	GLES3::Utilities::get_singleton()->buffer_allocate_data(GL_UNIFORM_BUFFER, new_buffers[2], sizeof(StateBuffer), nullptr, GL_STREAM_DRAW, "2D State UBO[" + itos(state.current_data_buffer_index) + "]");
	state.current_data_buffer_index = (state.current_data_buffer_index + 1);
	DataBuffer db;
	db.instance_buffers.push_back(new_buffers[0]);
	db.light_ubo = new_buffers[1];
	db.state_ubo = new_buffers[2];
	db.last_frame_used = RSG::rasterizer->get_frame_number();
	state.canvas_instance_data_buffers.insert(state.current_data_buffer_index, db);
	state.current_data_buffer_index = state.current_data_buffer_index % state.canvas_instance_data_buffers.size();
	glBindBuffer(GL_ARRAY_BUFFER, 0);
	glBindBuffer(GL_UNIFORM_BUFFER, 0);
}
void RasterizerCanvasGLES3::_allocate_instance_buffer() {