### 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 (p_line < 0 || p_line >= text.size()) {
		return "";
	}
	return text[p_line];
}
int TextEdit::get_line_width(int p_line, int p_wrap_index) const {
	ERR_FAIL_INDEX_V(p_line, text.size(), 0);
	ERR_FAIL_COND_V(p_wrap_index > get_line_wrap_count(p_line), 0);
	return text.get_line_width(p_line, p_wrap_index);
}
int TextEdit::get_line_height() const {
	return text.get_line_height() + line_spacing;
}
int TextEdit::get_indent_level(int p_line) const {
	ERR_FAIL_INDEX_V(p_line, text.size(), 0);
	int tab_count = 0;
	int whitespace_count = 0;
	int line_length = text[p_line].size();
	for (int i = 0; i < line_length - 1; i++) {
		if (text[p_line][i] == '\t') {
			tab_count++;
		} else if (text[p_line][i] == ' ') {
			whitespace_count++;
		} else {
			break;
		}
	}
	return tab_count * text.get_tab_size() + whitespace_count;
}
int TextEdit::get_first_non_whitespace_column(int p_line) const {