Select property button in TileSet Paint Editor is not toggleable

### Tested versions

Reproducible in: 4.3.1.dev [ff9bc04223] and 4.3 stable release

### System information

Godot v4.3.1.rc (ff9bc0422) - macOS 15.0.0 - Vulkan (Forward+) - integrated Apple M1 Max - Apple M1 Max (10 Threads)

### Issue description

In TileSet editor, the "Select a property editor" button is not toggleable. Clicking the button second time won't close the popup. It is a minor issue since the popup can be closed when clicking empty space.

Also, selecting the same property type won't close the popup.

### Steps to reproduce

1. Add a TileMap or TileMapLayer node in a new scene
2. Create a new TileSet
3. Focus on the TileSet editor
4. Create an atlas with icon.svg
5. Click to switch to Paint mode
6. Click the button "Select a property editor"
7. Click the button second time

Expect it to close when the popup is visible. Currently, I can click empty space to close the popup.

https://github.com/user-attachments/assets/0c47eef3-f1b2-4725-a14a-c35a51d1a5db

### Minimal reproduction project (MRP)

N/A

Start by reproducing the issue in the TileSet Paint Editor using the listed steps on Godot 4.3.1. Inspect the "Select a property editor" button and its popup behavior; done means clicking the button again, or selecting the same property type, closes the popup while clicking empty space continues to work.

Written by the indexing model from the issue text.