Reduce number of teams created in the seeds

[thomasleese]

This changes the seeds so that we don't create CIS2 teams in non-CIS2 environments, which means the seeds run quicker for local development.

There's definitely more we could do to improve the speed of seeding the database, but this helps a lot.

Before

❯ time bin/rails db:seed:replant
________________________________________________________
Executed in   76.13 secs    fish           external
   usr time   50.15 secs    0.20 millis   50.15 secs
   sys time    3.22 secs    1.70 millis    3.22 secs

After

❯ time bin/rails db:seed:replant
________________________________________________________
Executed in   43.53 secs    fish           external
   usr time   28.21 secs    0.34 millis   28.21 secs
   sys time    2.31 secs    2.03 millis    2.31 secs