### 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.
highlighted_text_col = _get_column_pos_of_word(highlighted_text, str, SEARCH_MATCH_CASE | SEARCH_WHOLE_WORDS, highlighted_text_col + highlighted_text_len);
						}
					}
					if (!clipped && lookup_symbol_word.length() != 0) { 
						if (is_ascii_char(lookup_symbol_word[0]) || lookup_symbol_word[0] == '_' || lookup_symbol_word[0] == '.') {
							int lookup_symbol_word_col = _get_column_pos_of_word(lookup_symbol_word, str, SEARCH_MATCH_CASE | SEARCH_WHOLE_WORDS, 0);
							int lookup_symbol_word_len = lookup_symbol_word.length();
							while (lookup_symbol_word_col != -1) {
								Vector<Vector2> sel = TS->shaped_text_get_selection(rid, lookup_symbol_word_col + start, lookup_symbol_word_col + lookup_symbol_word_len + start);
								for (int j = 0; j < sel.size(); j++) {
									Rect2 rect = Rect2(sel[j].x + char_margin + ofs_x, ofs_y + (line_spacing / 2), sel[j].y - sel[j].x, row_height);
									if (rect.position.x + rect.size.x <= xmargin_beg || rect.position.x > xmargin_end) {
										continue;
									}
									if (rect.position.x < xmargin_beg) {
										rect.size.x -= (xmargin_beg - rect.position.x);
										rect.position.x = xmargin_beg;
									} else if (rect.position.x + rect.size.x > xmargin_end) {
										rect.size.x = xmargin_end - rect.position.x;
									}
									rect.position.y += ceil(TS->shaped_text_get_ascent(rid)) + ceil(font->get_underline_position(font_size));
									rect.size.y = MAX(1, font->get_underline_thickness(font_size));
									draw_rect(rect, color);
								}
								lookup_symbol_word_col = _get_column_pos_of_word(lookup_symbol_word, str, SEARCH_MATCH_CASE | SEARCH_WHOLE_WORDS, lookup_symbol_word_col + lookup_symbol_word_len);
							}
						}
					}
					ofs_y += (row_height - text_height) / 2;
					const Glyph *glyphs = TS->shaped_text_get_glyphs(rid);