Pressing Ctrl/Alt + key works as a plain key press in the editor

### Tested versions

Reproducible in:
- v4.6.1.rc1.mono.official [7bfffc846] (Linux Fedora KDE)
- v4.6.stable.mono.official [89cea1439] (Linux Fedora KDE)
- v4.5.1.stable.official [f62fdbde1] (Linux Fedora KDE)

NOT reproducible in:
- v4.5.1 stable mono, (Windows 11)

### System information

Godot v4.6.1.rc1.mono - Fedora Linux 43 (KDE Plasma Desktop Edition) on Wayland - X11 display driver, Multi-window, 1 monitor - Vulkan (Forward+) - dedicated AMD Radeon RX 9060 XT (RADV GFX1200) - AMD Ryzen 7 9700X 8-Core Processor (16 threads) - 30.49 GiB memory

### Issue description

If I press `Ctrl + 1` or `Alt + 1` in the script editor, it works just like I would have pressed key `1` only, ie. character "1" appears. It seems that if a "modifier + key" doesn't have an assigned shortcut, the modifier is ignored.

I would expect that "modifier + key" press doesn't do anything if there is no shortcut assigned to this combo. This is how modifier keys work everywhere else.

### Steps to reproduce

- Check that you don't have shortcut assigned to `Ctrl + 1`
- Press `Ctrl + 1` in the script editor --> BUG: "1" appears

### Minimal reproduction project (MRP)

N/A