### 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
}
void TextureStorage::decal_set_albedo_mix(RID p_decal, float p_mix) {
}
void TextureStorage::decal_set_modulate(RID p_decal, const Color &p_modulate) {
}
void TextureStorage::decal_set_cull_mask(RID p_decal, uint32_t p_layers) {
}
void TextureStorage::decal_set_distance_fade(RID p_decal, bool p_enabled, float p_begin, float p_length) {
}
void TextureStorage::decal_set_fade(RID p_decal, float p_above, float p_below) {
}
void TextureStorage::decal_set_normal_fade(RID p_decal, float p_fade) {
}
AABB TextureStorage::decal_get_aabb(RID p_decal) const {
	return AABB();
}
GLuint TextureStorage::system_fbo = 0;
void TextureStorage::_update_render_target(RenderTarget *rt) {
	
	if (rt->size.x <= 0 || rt->size.y <= 0) {
		return;
	}
	
	if (rt->direct_to_screen) {
		rt->fbo = system_fbo;
		return;
	}
	Config *config = Config::get_singleton();
	rt->color_internal_format = rt->is_transparent ? GL_RGBA8 : GL_RGB10_A2;