[feat] Remove prefix on calendar events

[peyrin]

Google Calendar events should be prefixed "[CS188 SP25]" so that students adding it to their calendar see "[CS188 SP25] Lecture" instead of just "Lecture".

But, on the website itself, students should just see "Lecture" instead of "[CS188 SP25]" in front of all the calendar events.

I fixed this with one line of JS, will link it here and PR shortly.