### Godot version

4.0.stable.mono

### System information

Windows 10, NVIDIA RTX 2060 (Driver 30.0.14.7284), Vulkan 1.2.175 Forward+ (Editor)

### Issue description

When changing certain Global Shader Parameters (in this case, a mat4) in the Project Settings, the value sent to the editor 3D view appears to be undefined, resulting in garbage values sent to the shaders.

As an example here, I'm using a mat4 to describe global light directions for a lighting shader
Note that the shader receives a different value even when the editor is being set to the same values
https://user-images.githubusercontent.com/44537737/222551889-b7c7ca63-ef65-484c-818f-c6ce47a7d3c0.mp4

Setting the global parameter from a script does pass the correct value to the shaders
![image](https://user-images.githubusercontent.com/44537737/222552338-14582898-a76d-4ec4-b877-7b822e414901.png)

I have also determined the shaders in the editor also do not get correct values from the `project.godot` when loading the project.

### Steps to reproduce

- Create a Global Shader Parameter of mat4 type (Project > Project Settings... > Shader Globals)
- Create a shader that visualizes the value of the mat4 (`global uniform mat4 global_mat`)
- Attempt to modify the global in the same Project Settings menu, the shader will receive garbage values

### Minimal reproduction project

[GlobalShaderParameters.zip](https://github.com/godotengine/godot/files/10875801/GlobalShaderParameters.zip)

switch (p_op) {
		case OP_ASSIGN:
		case OP_ASSIGN_ADD:
		case OP_ASSIGN_SUB:
		case OP_ASSIGN_MUL:
		case OP_ASSIGN_DIV:
		case OP_ASSIGN_MOD:
		case OP_ASSIGN_SHIFT_LEFT:
		case OP_ASSIGN_SHIFT_RIGHT:
		case OP_ASSIGN_BIT_AND:
		case OP_ASSIGN_BIT_OR:
		case OP_ASSIGN_BIT_XOR:
			return true;
		default:
			return false;
	}
}
bool ShaderLanguage::_validate_varying_assign(ShaderNode::Varying &p_varying, String *r_message) {
	if (current_function != "vertex" && current_function != "fragment") {
		*r_message = vformat(RTR("Varying may not be assigned in the '%s' function."), current_function);
		return false;
	}
	switch (p_varying.stage) {
		case ShaderNode::Varying::STAGE_UNKNOWN: