### 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.
if (placeholder == p_text) {
		return;
	}
	placeholder = p_text;
	placeholder_translated = atr(placeholder);
	_shape();
	queue_redraw();
}
String LineEdit::get_placeholder() const {
	return placeholder;
}
void LineEdit::set_caret_column(int p_column) {
	if (p_column > (int)text.length()) {
		p_column = text.length();
	}
	if (p_column < 0) {
		p_column = 0;
	}
	caret_column = p_column;
	
	if (!is_inside_tree()) {
		scroll_offset = 0.0;
		return;
	}
	Ref<StyleBox> style = theme_cache.normal;
	bool rtl = is_layout_rtl();
	int x_ofs = 0;
	float text_width = TS->shaped_text_get_size(text_rid).x;
	switch (alignment) {