[NoNuke] Self updates can trigger actions

[EternalllZM]

Describe the bug A member updating their nickname rapidly can trigger nonuke.

Cog Version* 1.2.0

To Reproduce

1. Set nonuke to trigger on member_update
2. Set timer to something like 60 seconds
3. Change nickname twice in time period
4. NoNuke triggers

Expected behavior It shouldn't action on self updates. Furthermore, this user wasn't had no privileged roles or permissions. I am not sure this behavior is strict enough with its requirements before executing.