Exports not updating in Inspector when creating new class

[noahpete]

Tested versions

• Reproducible in: v4.3.stable, v4.4-beta1

System information

Godot v4.3.stable - Windows 10.0.22631 - Vulkan (Forward+) - dedicated NVIDIA GeForce RTX 3060 (NVIDIA; 31.0.15.5132) - 12th Gen Intel(R) Core(TM) i7-12700F (20 Threads)

Issue description

When creating an @export variable in a script before the variable's type exists, it will not be exposed in the Inspector even after the type is created. Only after restarting the application will the exported variable appear in the Inspector. Somewhat similar to #72319.

Steps to reproduce

1. Create a Node with script node.gd, and add the line @export var thing: Thing.
2. Create a new script, thing.gd, and add the line class_name Thing.
3. Observe that the Node with node.gd does not have thing exposed in the Inspector.

Minimal reproduction project (MRP)

N/A