Describe the bug
Freeing a node while it has a ShakerComponent shaking any of its properties makes the project crash because it tries to access a target Node that no longer exists.

To Reproduce

1. Create a sprite2D.
2. Call Shaker.shake_property(...) on its position during 1 second, enough to have time to delete the node before it finishes.
   queue_free the node via input(event) or process or whatever's quickest.

Expected behavior
I would expect Shaker to quietly halt any shake its running on freed nodes.

Screenshots
I added a target != null check in shaker_component.gd to see if that fixed the issue, but it doesn't, as can be seen in the screenshot:

Desktop (please complete the following information):

OS: Windows 10, 11
Shaker Version 1.6.0