[BUG] Recursive MadHatter initialization

[Pingdred]

Describe the bug
Calling MadHatter in the activated override of a plugin causes an infinite loop of MadHatter initialization.

To Reproduce
Steps to reproduce the behavior:

1. Create a new plugin.
2. Create a Python file and write the following code:

from cat.mad_hatter.decorators import plugin
from cat.mad_hatter.mad_hatter import MadHatter

@plugin
def activated(plugin):
    MadHatter()

Expected behavior
Since MadHatter is a singleton, it should be accessible from anywhere in the code without triggering reinitialization.

Additional context
This bug was introduced in CheshireCat version 1.8.0.