Fix tkinter dependency problem

[Bachibouzouk]

The error

~   File "/usr/local/lib/python3.12/site-packages/oemof/eesyplan/io.py", line 3, in <module>
~     from tkinter import Tk
~   File "/usr/local/lib/python3.12/tkinter/__init__.py", line 38, in <module>
~     import _tkinter # If this fails your Python may not be configured for Tk

Doesn't appear with the newest version of eesyplan, therefore one can remove the tk install step from the Dockerfile

Tested on sandbox