Perhaps the azan of Jumuah is called much before zawal. According to Hanafi Fiqh, neither there is azan before time nor any salah before time. You can offer sunnah after zawal when the time of Jumuah starts. It is not right to offer four rakah Jumuah sunnah before zawal.
Allah (Subhana Wa Ta’ala) knows Best
Darul Uloom Deoband