### Godot version

v4.1.dev.custom_build.a7276f1ce

### System information

Win10, AMD 2600, GeForce GTX 1060, Vulkan API 1.3.205

### Issue description

I can't get correct color data from an array of source_color type.
The color data is saved as **Color** in the file:
`shader_parameter/palette = [Color (1, 0, 0, 1), Color (0, 1, 0, 1), Color (0, 0, 1, 1)]`
Shouldn't it be saved as PackedColorArray?


### Steps to reproduce

1.Declare an array of source_color type.
2.Set colors.

### Minimal reproduction project

[shadertest.zip](https://github.com/godotengine/godot/files/11246504/shadertest.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: