### Godot version

4.0.2.stable.mono

### System information

Windows 10 - 4.0.2.stable.mono - Any Renderer

### Issue description

In a script with an `@export` variable (with a non-default value), Godot will replace the first variable in the category with the same name. For example, if you're exporting a variable called "Vector", and the value is set to a non-default value, the first variable in the category called "Vector" will also be changed to the same value.

### Steps to reproduce

Attach said script to a node:
```
extends Node

@export var Vector: Vector2
@export_category("Vector")
@export var Var2: float = 1

func _process(delta):
	print(Var2)
```
When changing the value of the `Vector` export variable, the variable Var2 will contain the same value. This does not happen when the `@export_category` has a different name.

### Minimal reproduction project

N/A
if (parsed_classes.has(p_script)) {
		return OK;
	}
	if (parsing_classes.has(p_script)) {
		String class_name = p_class->identifier ? String(p_class->identifier->name) : p_class->fqcn;
		_set_error(vformat(R"(Cyclic class reference for "%s".)", class_name), p_class);
		return ERR_PARSE_ERROR;
	}
	parsing_classes.insert(p_script);
	p_script->clearing = true;
	p_script->native = Ref<GDScriptNativeClass>();
	p_script->base = Ref<GDScript>();
	p_script->_base = nullptr;
	p_script->members.clear();
	
	HashMap<StringName, Variant> constants;
	for (const KeyValue<StringName, Variant> &E : p_script->constants) {
		constants.insert(E.key, E.value);
	}
	p_script->constants.clear();
	constants.clear();
	HashMap<StringName, GDScriptFunction *> member_functions;
	for (const KeyValue<StringName, GDScriptFunction *> &E : p_script->member_functions) {
		member_functions.insert(E.key, E.value);