You get locked out of the code editor after CtrL+Shift+U and then clicking somewhere

### Tested versions

Reproducible in 4.3

### System information

Godot v4.3.stable - Pop!_OS 22.04 LTS - X11 - GLES3 (Compatibility) - Mesa Intel(R) Graphics (ADL GT2) - 12th Gen Intel(R) Core(TM) i5-1235U (12 Threads)

### Issue description

The code in the script editor stops being editable when you click somewhere while you're inputting a unicode with Ctrl+Shift+U.

### Steps to reproduce

- Press Ctrl+Shift+U (or Ctrl+Shift+E if your system supports it). You'll see an underlined letter appear, which now prompts you to type something to input the unicode or emoji.
- Click somewhere in the code editor.
- You're now locked out and can't write code.

You can get edit access back by doing Ctrl+Shift+U again. The expected behavior would be that you exit unicode mode, or that you'd now be adding a unicode character in the new caret position (the latter seems to be how it's usually implemented).

### Minimal reproduction project (MRP)

N/A