### 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.
}
				accept_event();
				return;
			}
			return;
		}
		
		if (k->is_alt_pressed()) {
			if (!alt_start) {
				if (k->get_keycode() == Key::KP_ADD) {
					alt_start = true;
					alt_code = 0;
					accept_event();
					return;
				}
			} else {
				if (k->get_keycode() >= Key::KEY_0 && k->get_keycode() <= Key::KEY_9) {
					alt_code = alt_code << 4;
					alt_code += (uint32_t)(k->get_keycode() - Key::KEY_0);
				}
				if (k->get_keycode() >= Key::KP_0 && k->get_keycode() <= Key::KP_9) {
					alt_code = alt_code << 4;
					alt_code += (uint32_t)(k->get_keycode() - Key::KP_0);
				}
				if (k->get_keycode() >= Key::A && k->get_keycode() <= Key::F) {
					alt_code = alt_code << 4;
					alt_code += (uint32_t)(k->get_keycode() - Key::A) + 10;
				}
				accept_event();
				return;