### 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 (operand.mode == GDScriptCodeGenerator::Address::TEMPORARY) {
				gen->pop_temporary();
			}
			return result;
		} break;
		case GDScriptParser::Node::ASSIGNMENT: {
			const GDScriptParser::AssignmentNode *assignment = static_cast<const GDScriptParser::AssignmentNode *>(p_expression);
			if (assignment->assignee->type == GDScriptParser::Node::SUBSCRIPT) {
				
				const GDScriptParser::SubscriptNode *subscript = static_cast<GDScriptParser::SubscriptNode *>(assignment->assignee);
#ifdef DEBUG_ENABLED
				if (subscript->is_attribute && subscript->base->type == GDScriptParser::Node::SELF && codegen.script) {
					HashMap<StringName, GDScript::MemberInfo>::Iterator MI = codegen.script->member_indices.find(subscript->attribute->name);
					if (MI && MI->value.setter == codegen.function_name) {
						String n = subscript->attribute->name;
						_set_error("Must use '" + n + "' instead of 'self." + n + "' in setter.", subscript);
						r_error = ERR_COMPILATION_FAILED;
						return GDScriptCodeGenerator::Address();
					}
				}
#endif
				
				StringName assign_class_member_property;
				GDScriptCodeGenerator::Address target_member_property;
				bool is_member_property = false;
				bool member_property_has_setter = false;
				bool member_property_is_in_setter = false;
				bool is_static = false;
				GDScriptCodeGenerator::Address static_var_class;
				int static_var_index = 0;