apps/speed.c: Fix the benchmarking for AEAD ciphers

Fixed the benchmarking for the evp aead interface for ccm, gcm, ocb, and siv,
where decryption fails when executing
`openssl speed -evp aes-128-ccm -decrypt` and
`openssl speed -evp aes-128-gcm -decrypt`.

Related issues are [24686](openssl#24686)
and [24250](openssl#24250).
Now both encryption and decryption, with or without AAD, executes correctly
without issues.

Reviewed-by: Tom Cosgrove <[email protected]>
Reviewed-by: Tomas Mraz <[email protected]>
(Merged from openssl#25823)