### 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?)
Vector<String> subindices;
	if (r_valid) {
		*r_valid = true;
	}
	switch (p_type) {
		case Variant::INT: {
			subindices.push_back("");
		} break;
		case Variant::FLOAT: {
			subindices.push_back("");
		} break;
		case Variant::VECTOR2: {
			subindices.push_back(":x");
			subindices.push_back(":y");
		} break;
		case Variant::VECTOR3: {
			subindices.push_back(":x");