bug(ios): Predictions and Corrections toggles should be disabled if no dictionaries installed

In Keyman for iOS, I installed a new keyboard, and the switches for Predictions and Corrections were active and enabled by default. That was even with no dictionary installed.

That doesn't make much sense as those options should not be available until there is a dictionary, right? After a dictionary is installed, we can activate them and default them as enabled. Until then they should be disabled and inactive.

_Originally posted by @sgschantz in https://github.com/keymanapp/keyman/issues/6197#issuecomment-1028781490_