MultiplayerSynchronizer: adding duplicate properties makes editor unresponsive

[alpapaydin]

Tested versions

4.3.stable.official

System information

Godot v4.3.stable - Windows 10.0.19045 - Vulkan (Forward+) - dedicated NVIDIA GeForce RTX 3080 Laptop GPU (NVIDIA; 32.0.15.7216) - Intel(R) Core(TM) i7-10870H CPU @ 2.20GHz (16 Threads)

Issue description

When adding a property to MultiplayerSynchronizer via replication tab, if that property already exists, the next time you try to add a new property editor freezes and becomes unresponsive.

Steps to reproduce

Just try to add position property to any multiplayer synchronizer in node_3d scene, try to add it again, then open adding window again.

Minimal reproduction project (MRP)

reproduction.zip