You didn’t, thanks for saying that Maybe with one comment: the phone will stop drawing power automatically once the voltage drops below a certain threshold, and setting a high value won’t necessarily mean that it will draw that much power (it’s just the maximum limit), so with well-behaving chargers it shouldn’t really be dangerous. However, keep in mind that not all chargers are well-behaving.
Let me stress the importance of another warning though:
i2cset is a low level tool that allows you to directly set certain hardware registers. Always make sure you have typed the arguments correctly since you may be one typo away from breaking your hardware. When it doubt, consult the datasheet.