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

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](https://github.com/openssl/openssl/issues/24686)
and [24250](https://github.com/openssl/openssl/issues/24250).
Now both encryption and decryption, with or without AAD, executes correctly
without issues.

Reviewed-by: Tom Cosgrove <tom.cosgrove@arm.com>
Reviewed-by: Tomas Mraz <tomas@openssl.org>
(Merged from https://github.com/openssl/openssl/pull/25823)