### 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.
dragging_selection = true;
	Point2 mp = get_local_mouse_pos();
	Point2i pos = get_line_column_at_pos(mp);
	int line = pos.y;
	int col = pos.x;
	int caret_idx = carets.size() - 1;
	int caret_pos = CLAMP(col, 0, text[line].length());
	int beg = caret_pos;
	int end = beg;
	PackedInt32Array words = TS->shaped_text_get_word_breaks(text.get_line_data(line)->get_rid());
	for (int i = 0; i < words.size(); i = i + 2) {
		if ((words[i] < caret_pos && words[i + 1] > caret_pos) || (i == words.size() - 2 && caret_pos == words[i + 1])) {
			beg = words[i];
			end = words[i + 1];
			break;
		}
	}