إِلَى عَبْدِكَ الْعَاصِي أَتَاكَا
Your disobedient servant has come to You.
مُقِرًّا بِالذُّنُوبِ وَقَدْ دَعَاكَا
Confessing his sins, he calls upon You.
Instead of a plain first-person formulation, the explicit description «عبدك العاصي» presents dependence, disobedience and confession together. The rhetorical motive is to elicit mercy and sympathy through an appeal in supplication.
Both “Your servant” and “disobedient” carry meaning that a bare pronoun would not convey with equal specificity.