Fix "Remember window size" not working when unchecked

When this feature is turned off, it deletes some keys from Konsole's
config file. However this broke recently for two reasons:

1. The key names changed a few Frameworks releases ago
2. There are new keys that need to be deleted or else position gets
   restored too

This commit fixes that bug by updating the condition to delete all the
config keys required to make the off state for this feature work again.

BUG: 427610
FIXED-IN: 20.12.2