### Godot version

v4.0.beta17.official [c40020513]

### System information

Windows 11, OpenGL (Compatibility), RTX 2060 (31.0.15.2824)

### Issue description

I tried to make a blurred panel for a ui element with texturelod via shader:

```glsl
shader_type canvas_item;

uniform sampler2D SCREEN_TEXTURE : hint_screen_texture, filter_linear_mipmap_anisotropic;
uniform float blur_amount : hint_range(0.0, 5.0);

void fragment() {
	vec4 blurred = textureLod(SCREEN_TEXTURE, SCREEN_UV, blur_amount);
	COLOR = blurred;
}
```

but what I got instead is this:
![image](https://user-images.githubusercontent.com/72286622/217170426-49f6712d-47ef-4c53-b9f1-30d8ad868084.png)

vulkan renderer does not exhibit this issue:
![image](https://user-images.githubusercontent.com/72286622/217170565-a013c712-94f6-49d1-b9ec-091c28a7790b.png)


### Steps to reproduce

1. Add a TextureRect node
2. Add a Panel node to overlay the previously added node
3. Apply the blur shader to the panel node

### Minimal reproduction project

N/A
private:
	struct Copy {
		CopyShaderGLES3 shader;
		RID shader_version;
	} copy;
	static CopyEffects *singleton;
	
	GLuint screen_triangle = 0;
	GLuint screen_triangle_array = 0;
	
	GLuint quad = 0;
	GLuint quad_array = 0;
public:
	static CopyEffects *get_singleton();
	CopyEffects();
	~CopyEffects();
	
	void copy_to_rect(const Rect2 &p_rect);
	void copy_screen();
	void bilinear_blur(GLuint p_source_texture, int p_mipmap_count, const Rect2i &p_region);
	void set_color(const Color &p_color, const Rect2i &p_region);
	void draw_screen_triangle();
	void draw_screen_quad();
};
} 
#endif 
#endif