Stove igniter producing electric shock
I assume that the igniter is igniting the gas.
IF the shock is caused by the igniter piezo unit and
IF the igniter works
THEN it sounds as if the igniter IS grounded (at least locally) to the stove main metal work
BUT that the stove top proper is not.
Use an ohm meter (a DMM feature) to check DC resistance from bare metal on stove top to stove main body metalwork.
This should be a few Ohms at worst and probably under 1 Ohm.
IF the top is not properly grounded make it so.