### 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.
k = k->duplicate();
		bool shift_pressed = k->is_shift_pressed();
		
		k->set_shift_pressed(false);
		if (k->is_action("ui_text_caret_word_left", true)) {
			_move_caret_left(shift_pressed, true);
			accept_event();
			return;
		}
		if (k->is_action("ui_text_caret_left", true)) {
			_move_caret_left(shift_pressed);
			accept_event();
			return;
		}
		if (k->is_action("ui_text_caret_word_right", true)) {
			_move_caret_right(shift_pressed, true);
			accept_event();
			return;
		}
		if (k->is_action("ui_text_caret_right", true)) {
			_move_caret_right(shift_pressed, false);
			accept_event();
			return;
		}
		
		if (k->is_action("ui_text_caret_up", true) || k->is_action("ui_text_caret_line_start", true) || k->is_action("ui_text_caret_page_up", true)) {
			_move_caret_start(shift_pressed);
			accept_event();
			return;
		}