### Godot version

4.0.dev (c309de53997feff3286295fb2d71657f112a15db)

### System information

Linux, Nvidia, Vulkan

### Issue description

Editor segfaults when certain conditions are met when using the AnimationPlayer editor.

### Steps to reproduce

1. Create multiple animations, saved into a animation collection
2. Open an existing animation, then make a new empty animation
3. Change from seconds to fps, or add a new property to animate ()
4. Editor crashes

NOTE: It is slightly random and I have not found a perfect repro

### Minimal reproduction project

N/A (TBD?)
if (!path) {
			path_popup = memnew(Popup);
			path_popup->set_wrap_controls(true);
			add_child(path_popup);
			path = memnew(LineEdit);
			path_popup->add_child(path);
			path->set_anchors_and_offsets_preset(PRESET_FULL_RECT);
			path->connect("text_submitted", callable_mp(this, &AnimationTrackEdit::_path_submitted));
		}
		path->set_text(animation->track_get_path(track));
		Vector2 theme_ofs = path->get_theme_stylebox(SNAME("normal"), SNAME("LineEdit"))->get_offset();
		path_popup->set_position(get_screen_position() + path_rect.position - theme_ofs);
		path_popup->set_size(path_rect.size);
		path_popup->popup();
		path->grab_focus();
		path->set_caret_column(path->get_text().length());
		clicking_on_name = false;
	}
	if (mb.is_valid() && moving_selection_attempt) {
		if (!mb->is_pressed() && mb->get_button_index() == MouseButton::LEFT) {
			moving_selection_attempt = false;
			if (moving_selection) {
				emit_signal(SNAME("move_selection_commit"));
			} else if (select_single_attempt != -1) {
				emit_signal(SNAME("select_key"), select_single_attempt, true);
			}
			moving_selection = false;
			select_single_attempt = -1;
		}
		if (moving_selection && mb->is_pressed() && mb->get_button_index() == MouseButton::RIGHT) {