### 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 (subscript->base->type == GDScriptParser::Node::SELF && codegen.script) {
					GDScriptParser::IdentifierNode *identifier = subscript->attribute;
					HashMap<StringName, GDScript::MemberInfo>::Iterator MI = codegen.script->member_indices.find(identifier->name);
#ifdef DEBUG_ENABLED
					if (MI && MI->value.getter == codegen.function_name) {
						String n = identifier->name;
						_set_error("Must use '" + n + "' instead of 'self." + n + "' in getter.", identifier);
						r_error = ERR_COMPILATION_FAILED;
						return GDScriptCodeGenerator::Address();
					}
#endif
					if (MI && MI->value.getter == "") {
						
						gen->pop_temporary();
						
						return GDScriptCodeGenerator::Address(GDScriptCodeGenerator::Address::MEMBER, MI->value.index, _gdtype_from_datatype(subscript->get_datatype(), codegen.script));
					}
				}
				name = subscript->attribute->name;
				named = true;
			} else {
				if (subscript->index->is_constant && subscript->index->reduced_value.get_type() == Variant::STRING_NAME) {
					
					name = subscript->index->reduced_value;
					named = true;
				} else {
					
					index = _parse_expression(codegen, r_error, subscript->index);
					if (r_error) {
						return GDScriptCodeGenerator::Address();