[E2E] Set old_otp variable to use current_otp

What does this MR do and why?

As per the failure message undefined local variable or method otp we can see this is a typo.
The method signature suggests that we should be providing the 'old_otp' to verify that we do in fact get a new one, so in this case we should be passing current_otp to the method.

Fixes #438352 (closed)

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