Proposed change: Do not update output path when changing preferences

[B-Hartmann]

The line

MPL-Data-Cast/mpl_data_cast/gui/main.py

Line 134 in ffdced0

self.widget_output.path = self.settings.value("main/output_path",

causes the current output path to be changed to the new default output path from the preferences in case the user updates the preferences.
I propose to remove that line of code, because I find it confusing and surprising that the current output directory in the main window changes because of a change in the preferences.
I think that users would anyway first change the directory in the main gui and then decide to have that directory as default for the future and update the preferences, not the other way around.