### Godot version

4.0 beta 15

### System information

Windows 10

### Issue description

It happened with both Google IME and MS-IME, and there was no problem until Beta14.
When typing Japanese characters, it is common to select a character from the suggestion window and then start typing the next character before confirming.
In this case, uncommitted characters are forcibly committed, and input of the next character begins.

**↓Beta15**

https://user-images.githubusercontent.com/186786/214753450-b493cca6-2644-4b3d-8cd2-660565cc3547.mp4

**↓Beta14**

https://user-images.githubusercontent.com/186786/214755127-dde819cc-4d63-403a-99b0-09821671f74e.mp4



### Steps to reproduce

It happened with both Google IME and MS-IME in beta15

### Minimal reproduction project

It is project independent and happens in the editor.
StringBuilder ret_text;
	const int text_size = text.size();
	for (int i = 0; i < text_size; i++) {
		ret_text += text[i];
		if (i != text_size - 1) {
			ret_text += "\n";
		}
	}
	return ret_text.as_string();
}
int TextEdit::get_line_count() const {
	return text.size();
}
void TextEdit::set_placeholder(const String &p_text) {