### 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 (!menu) {
		menu = memnew(PopupMenu);
		add_child(menu, false, INTERNAL_MODE_FRONT);
		menu_dir = memnew(PopupMenu);
		menu_dir->set_name("DirMenu");
		menu_dir->add_radio_check_item(RTR("Same as Layout Direction"), MENU_DIR_INHERITED);
		menu_dir->add_radio_check_item(RTR("Auto-Detect Direction"), MENU_DIR_AUTO);
		menu_dir->add_radio_check_item(RTR("Left-to-Right"), MENU_DIR_LTR);
		menu_dir->add_radio_check_item(RTR("Right-to-Left"), MENU_DIR_RTL);
		menu->add_child(menu_dir, false, INTERNAL_MODE_FRONT);
		menu_ctl = memnew(PopupMenu);
		menu_ctl->set_name("CTLMenu");
		menu_ctl->add_item(RTR("Left-to-Right Mark (LRM)"), MENU_INSERT_LRM);
		menu_ctl->add_item(RTR("Right-to-Left Mark (RLM)"), MENU_INSERT_RLM);
		menu_ctl->add_item(RTR("Start of Left-to-Right Embedding (LRE)"), MENU_INSERT_LRE);
		menu_ctl->add_item(RTR("Start of Right-to-Left Embedding (RLE)"), MENU_INSERT_RLE);
		menu_ctl->add_item(RTR("Start of Left-to-Right Override (LRO)"), MENU_INSERT_LRO);
		menu_ctl->add_item(RTR("Start of Right-to-Left Override (RLO)"), MENU_INSERT_RLO);
		menu_ctl->add_item(RTR("Pop Direction Formatting (PDF)"), MENU_INSERT_PDF);
		menu_ctl->add_separator();
		menu_ctl->add_item(RTR("Arabic Letter Mark (ALM)"), MENU_INSERT_ALM);
		menu_ctl->add_item(RTR("Left-to-Right Isolate (LRI)"), MENU_INSERT_LRI);
		menu_ctl->add_item(RTR("Right-to-Left Isolate (RLI)"), MENU_INSERT_RLI);
		menu_ctl->add_item(RTR("First Strong Isolate (FSI)"), MENU_INSERT_FSI);
		menu_ctl->add_item(RTR("Pop Direction Isolate (PDI)"), MENU_INSERT_PDI);
		menu_ctl->add_separator();
		menu_ctl->add_item(RTR("Zero-Width Joiner (ZWJ)"), MENU_INSERT_ZWJ);
		menu_ctl->add_item(RTR("Zero-Width Non-Joiner (ZWNJ)"), MENU_INSERT_ZWNJ);
		menu_ctl->add_item(RTR("Word Joiner (WJ)"), MENU_INSERT_WJ);