The KeyBindingsList dialog tries to connect to non-existent signals

[mbrlabs]

Lorien version:
main branch, b017256

OS/device including version:
Windows 11

Issue description:
Many errors (66) of this kind:

E 0:00:01.142   Object::connect: In Object of type 'Label': Attempt to connect nonexistent signal 'bind_new_key' to method 'Control._bind_new_key'.
  <C++ Error>   Condition "!signal_is_valid" is true. Returned: ERR_INVALID_PARAMETER
  <C++ Source>  core\object.cpp:1462 @ Object::connect()
  <Stack Trace> KeyBindingsList.gd:47 @ _new_keybinding_entry()
                KeyBindingsList.gd:29 @ _populate_input_list()
                KeyBindingsList.gd:12 @ _ready()

Which happens in here:

Lorien/lorien/UI/Dialogs/KeyBindingsList.gd

Lines 46 to 47 in b017256

	child.connect("modified_binding", self, "_modify_keybinding", [action_name])
	child.connect("bind_new_key", self, "_bind_new_key", [action_name])

It doesn't seem to have any negative effects though in a debug build. We should check if the child is the right type/node before trying to connect the signal. @MrApplejuice

Steps to reproduce:
Just launch Lorien in the editor and observe the Debugger error tab