### Godot version

4.0.beta10.official [d0398f62f]

### System information

Windows 10, Vulkan, NVIDIA GeForce RTX 2060m (31.0.15.2698)

### Issue description

I'm getting some kind of clustering/blocky artifact when using spotlights, with no fog or any fancy rendering stuff whatsoever.
I've looked through a bunch of similar issues, but the only ones I could find were related to volumetric fog or other environment effects that I am not using.
Not sure if I'm just missing something, but I think I've played with every option in the spotlight and every option in a WorldEnvironment and nothing makes it go away.

The only lead I have is that the intensity of the artifact seems to be affected by the spot angle. It cycles in a sawtooth pattern every ~0.07 degrees.

![image](https://user-images.githubusercontent.com/13819558/209914720-77a637ea-8cc7-4cff-8216-363f9150885a.png)

Lmk if you need more info or need me to try anything.

### Steps to reproduce

1. New Project (Forward+)
2. Put down some MeshInstance3Ds as a backdrop
3. Put a SpotLight3D
4. Raise spotlight intensity, lower spot angle, and increase range to see it better
5. Slowly increase spot angle to see cycling effect

### Minimal reproduction project

[testspotlight.zip](https://github.com/godotengine/godot/files/10318069/testspotlight.zip)

#include "core/config/project_settings.h"
#include "light_3d.h"
void Light3D::set_param(Param p_param, real_t p_value) {
	ERR_FAIL_INDEX(p_param, PARAM_MAX);
	param[p_param] = p_value;
	RS::get_singleton()->light_set_param(light, RS::LightParam(p_param), p_value);
	if (p_param == PARAM_SPOT_ANGLE || p_param == PARAM_RANGE) {
		update_gizmos();
		if (p_param == PARAM_SPOT_ANGLE) {
			update_configuration_warnings();
		}
	}
}
real_t Light3D::get_param(Param p_param) const {
	ERR_FAIL_INDEX_V(p_param, PARAM_MAX, 0);
	return param[p_param];
}
void Light3D::set_shadow(bool p_enable) {
	shadow = p_enable;
	RS::get_singleton()->light_set_shadow(light, p_enable);
	if (type == RenderingServer::LIGHT_SPOT || type == RenderingServer::LIGHT_OMNI) {
		update_configuration_warnings();
	}
	notify_property_list_changed();
}
bool Light3D::has_shadow() const {