### 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_search_flags & SEARCH_BACKWARDS) {
				from_column = text_line.length() - 1;
			} else {
				from_column = 0;
			}
		}
		pos = -1;
		int pos_from = (p_search_flags & SEARCH_BACKWARDS) ? text_line.length() : 0;
		int last_pos = -1;
		while (true) {
			if (p_search_flags & SEARCH_BACKWARDS) {
				while ((last_pos = (p_search_flags & SEARCH_MATCH_CASE) ? text_line.rfind(p_key, pos_from) : text_line.rfindn(p_key, pos_from)) != -1) {
					if (last_pos <= from_column) {
						pos = last_pos;
						break;
					}
					pos_from = last_pos - p_key.length();
					if (pos_from < 0) {
						break;
					}
				}
			} else {
				while ((last_pos = (p_search_flags & SEARCH_MATCH_CASE) ? text_line.find(p_key, pos_from) : text_line.findn(p_key, pos_from)) != -1) {
					if (last_pos >= from_column) {
						pos = last_pos;
						break;
					}
					pos_from = last_pos + p_key.length();
				}
			}