Update /pricing/ page with AM3 Billing info

[coolguyzone]

Which part? Which one?

Pricing & Billing

Description

Update to pricing docs, see https://www.notion.so/sentry/Pricing-Docs-dc9e21de12f3486fb446be3aae08368d?d=12f8b10e4b5d80f392d0001c13e4470d for reference.

Suggested Solution

Open a PR with changes as noted in Notion link above.

[getsantry]

Assigning to @getsentry/support for routing ⏲️