Remove monthly/yearly toggle + pricing from new Team Types page

[n-lark]

Acceptance criteria

• Remove the monthly/yearly toggle from the team type page - we only have yearly.

[knolleary]

To clarify - the toggle is used to change what pricing is shown for each tier.

With the new tiers, we're not going to show pricing on the page at all (for now). The toggle doesn't serve a purpose.

As I see it, there are two options:

1. just remove the component (can be added back in the future if things change)
2. add some logic to check the billing details of the team types - if they are all missing the monthly billing description and yearly billing description, then hide the toggle as there's nothing to show.

There is some lingering logic around treating a blank billing description to mean 'free'. That may trip up the logic of 2 - we don't need free tiers these days, so that could be removed.