### Godot version

4.0.2.stable

### System information

Ubuntu 22.10

### Issue description

This happens when converting a godot3 project to a godot4 project.
Godot3 source
```gdscript
extends Node2D

export(int) var integer := 2
export(Resource) var resource: Resource = null
```

Result
```gdscript
extends Node2D

@export var integer: int := 2
@export var resource: Resource: Resource = null
```

Expected result
```gdscript
extends Node2D

@export var integer := 2
@export var resource: Resource = null
```

If someone can point to where in the code this might be fixed maybe I can fix it myself, sounds like a good first issue.


### Steps to reproduce

Open the given project (or any project really) and convert it to a godot 4 project

### Minimal reproduction project

[Conversion Tool Typing Problem.zip](https://github.com/godotengine/godot/files/11185334/Conversion.Tool.Typing.Problem.zip)

bool valid = true;
	Vector<String> names = Vector<String>();
	
	{
		for (unsigned int current_index = 0; RenamesMap3To4::class_renames[current_index][0]; current_index++) {
			const String old_class = RenamesMap3To4::class_renames[current_index][0];
			const String new_class = RenamesMap3To4::class_renames[current_index][1];
			
			if (ClassDB::class_exists(StringName(old_class)) && old_class != "Light2D" && old_class != "Texture" && old_class != "Viewport") {
				ERR_PRINT(vformat("Class \"%s\" exists in Godot 4.0, so it cannot be renamed to something else.", old_class));
				valid = false; 
			}
			
			if (!ClassDB::class_exists(StringName(new_class)) && new_class != "Callable") {
				ERR_PRINT(vformat("Class \"%s\" does not exist in Godot 4.0, so it cannot be used in the conversion.", old_class));
				valid = false; 
			}