Update MASWE-0023 (by @NowSecure)

[cpholguera]

1. Changed PKCS#5 to PKCS#7 in Document/0x04g-Testing-Cryptography.md:

   • Corrected the reference from PKCS#5 to PKCS#7 which is the correct one.

2. Refined the language in MASVS-CRYPTO/MASWE-0014:

   • Changed "Data Tampering" to "Loss of Integrity."
   • This aligns terminology used in other weaknesses, for consistency.

3. Expanded on padding oracle attacks in MASWE-0023:

   • Enhanced the explanation by including the role of error messages and the importance of additional mitigations like HMAC or authenticated modes.
   • Added clarity on conditions for the attack:
     • Lack of message authentication.
     • Feedback mechanisms that create a "padding oracle."
   • Updated mitigations:
     • Highlighted the use of Encrypt-then-MAC (EtM) with AES-CBC if AES-GCM isn't feasible.
     • Reinforced that cryptographic errors (like padding or MAC errors) should never be exposed to users.

[cpholguera]

I fully agree with your comments, @serek8. Please review the new version of the content.