### Godot version

4.0.2.stable.official.7a0977ce2

### System information

Linux

### Issue description

The following code fails with godot-cpp
```c++
Variant variant_int = 1234;
double double_value = variant_int;
UtilityFunctions::print(double_value); // prints 0. it must be 1234

Variant double_variant = 6789.0;
int int_value = double_variant;
UtilityFunctions::print(int_value); // prints 0. it must be 1234

Variant variant_string = "12345";
StringName string_name = variant_string;
UtilityFunctions::print(string_name); // Segmentation Fault!
```

When godot-cpp converts a `Variant` to another type, it calls `type_from_variant_constructor` without checking its type. It only does  `reinterpret_cast` and does no type conversion.
I think this issue can be solved by implementing type conversion on the godot-cpp side or by making `type_from_variant_constructor` do the type conversion.

### Steps to reproduce

Unzip the minimal reproduction project and run `scons` to build the GDExtension.

### Minimal reproduction project

[variant-conversion-issue.zip](https://github.com/godotengine/godot/files/11171860/variant-conversion-issue.zip)

static _FORCE_INLINE_ const Variant &get(const Variant *v) { return *v; }
	static _FORCE_INLINE_ void set(Variant *v, const Variant &p_value) { *v = p_value; }
};
template <>
struct VariantInternalAccessor<Vector<Variant>> {
	static _FORCE_INLINE_ Vector<Variant> get(const Variant *v) {
		Vector<Variant> ret;
		int s = VariantInternal::get_array(v)->size();
		ret.resize(s);
		for (int i = 0; i < s; i++) {
			ret.write[i] = VariantInternal::get_array(v)->get(i);
		}
		return ret;
	}
	static _FORCE_INLINE_ void set(Variant *v, const Vector<Variant> &p_value) {
		int s = p_value.size();
		VariantInternal::get_array(v)->resize(s);
		for (int i = 0; i < s; i++) {
			VariantInternal::get_array(v)->set(i, p_value[i]);
		}
	}
};
template <class T>
struct VariantInitializer {
};
template <>
struct VariantInitializer<bool> {
	static _FORCE_INLINE_ void init(Variant *v) { VariantInternal::init_generic<bool>(v); }