Guard against calling optional ftfy module if not available

[awsr]

What does this PR do?

Fixes NameError: name 'ftfy' is not defined

This was encountered by one of our users on SDNext. I'm not entirely sure why ftfy didn't get installed, but if it's optionally imported then it should also be optionally called.

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Tagging: @sayakpaul @yiyixuxu @DN6

[awsr]

I added all the missing ftfy checks that would cause exceptions. I had originally added explicit checks to other uses, but I reverted those because they're not related to this particular issue and aren't actual errors.