Editor dropdown button should have consistent margins on all sides

[fazil47]

Godot version

4.x

System information

Windows 11 - Godot 4.x

Issue description

Not sure if it's conscious design decision (feel free to close this if it is), but the margins on all sides of a dropdown button should be the same for consistency. It also looks pretty bad with rounded corners IMO.

How it looks now:

How it should look like:

Steps to reproduce

1. Open a new project.
2. Add a new 3D scene.
3. Add a new mesh instance.
4. Click on the mesh property dropdown button and add a new mesh.
5. Look at the margins of the dropdown button.

Minimal reproduction project

N/A

[timothyqiu]

It does not have any margin actually. The bottom margin you see is the separation between the property row and the detailed resource view below.