### Godot version

v4.1.beta.custom_build [d3651ea45]

### System information

Windows 11

### Issue description

![1](https://github.com/godotengine/godot/assets/28705694/15c14c93-7ad7-425a-8fb0-bef841b75527)

It's not possible to start text selection on a SpinBox when it's unfocused.

Note: After a bit of digging in the code, I found that clicking on a SpintBox doesn't trigger `SpinBox::gui_input` no matter if it's focused or not. However, releasing mouse left button does trigger the function.

### Steps to reproduce

See the gif.

### Minimal reproduction project

It's simple to reproduce.
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);