Signal checking / management functions don't work if signal was connected using "+=" C#

[ZachAR3]

Godot version

4.0.3.stable.mono

System information

Endeavour OS Zen Kernel 6.3 Ryzen 5900x Nvidia RTX 2080TI 11GB (proprietary drivers)

Issue description

When connecting a nodes signal to a local function using += in C# functions such as IsConnected or Disconnect don't recognize the signals connected and therefore fail / return nothing.

Steps to reproduce

1. Connect a nodes signal to a local function using Node.signal += localFunction;
2. Attempt to use a signal controller that requires finding the signal such as `IsConnected'
3. It won't recognize the existence of the signal and in the case of IsConnected will return false always.

Minimal reproduction project

N/A

[akien-mga]

Duplicate of #70414