### 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.
ERR_FAIL_INDEX_V(p_line, text.size(), Color());
	return text.get_line_background_color(p_line);
}
void TextEdit::set_syntax_highlighter(Ref<SyntaxHighlighter> p_syntax_highlighter) {
	if (syntax_highlighter == p_syntax_highlighter && syntax_highlighter.is_valid() == p_syntax_highlighter.is_valid()) {
		return;
	}
	syntax_highlighter = p_syntax_highlighter;
	if (syntax_highlighter.is_valid()) {
		syntax_highlighter->set_text_edit(this);
	}
	queue_redraw();
}
Ref<SyntaxHighlighter> TextEdit::get_syntax_highlighter() const {
	return syntax_highlighter;
}
void TextEdit::set_highlight_current_line(bool p_enabled) {
	if (highlight_current_line == p_enabled) {
		return;
	}
	highlight_current_line = p_enabled;
	queue_redraw();
}
bool TextEdit::is_highlight_current_line_enabled() const {