Remove log_verification_user_not_found method from identity verification

What does this MR do and why?

• Follows from !130799 (merged)
• Since merging the above^ MR, we are no longer receiving logs for when a user is logged in/verified but are experiencing an error during the identity verification process. Hence, we don't need this debugging log anymore.

Screenshots or screen recordings

Logs

MR acceptance checklist

This checklist encourages us to confirm any changes have been analyzed to reduce risks in quality, performance, reliability, security, and maintainability.

• I have evaluated the MR acceptance checklist for this MR.