### 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
CanvasTexture *ct = canvas_texture_owner.get_or_null(p_canvas_texture);
	ERR_FAIL_NULL(ct);
	ct->specular_color.r = p_specular_color.r;
	ct->specular_color.g = p_specular_color.g;
	ct->specular_color.b = p_specular_color.b;
	ct->specular_color.a = p_shininess;
}
void TextureStorage::canvas_texture_set_texture_filter(RID p_canvas_texture, RS::CanvasItemTextureFilter p_filter) {
	CanvasTexture *ct = canvas_texture_owner.get_or_null(p_canvas_texture);
	ERR_FAIL_NULL(ct);
	ct->texture_filter = p_filter;
}
void TextureStorage::canvas_texture_set_texture_repeat(RID p_canvas_texture, RS::CanvasItemTextureRepeat p_repeat) {
	CanvasTexture *ct = canvas_texture_owner.get_or_null(p_canvas_texture);
	ERR_FAIL_NULL(ct);
	ct->texture_repeat = p_repeat;
}
Ref<Image> TextureStorage::_get_gl_image_and_format(const Ref<Image> &p_image, Image::Format p_format, Image::Format &r_real_format, GLenum &r_gl_format, GLenum &r_gl_internal_format, GLenum &r_gl_type, bool &r_compressed, bool p_force_decompress) const {
	Config *config = Config::get_singleton();
	r_gl_format = 0;
	Ref<Image> image = p_image;
	r_compressed = false;
	r_real_format = p_format;
	bool need_decompress = false;
	bool decompress_ra_to_rg = false;
	switch (p_format) {
		case Image::FORMAT_L8: {
#ifdef GLES_OVER_GL
			r_gl_internal_format = GL_R8;
			r_gl_format = GL_RED;