Subscription notification - Be able to setup notifications on more than 100% consumption of the org

### Problem Statement

Sentry currently has a way to configure your consumption alert up until 90% where 100% is always on.
But there are customers that have a true forward (unlimited quota after 100% consumption).

This does not fit in the "Pay-as-you-go Consumption" as there is technically no other budget except unlimited.

So in the end this brings back the need to get alerted if you spend 150% of your total budget for instance so the admin team can take action if that happens to quickly

### Solution Brainstorm

Extend the configurable limits to more than 100%

### Product Area

Settings - Subscription

Start in the Settings–Subscription consumption-alert configuration and trace how the existing 90% and always-on 100% limits are represented. Done means administrators can configure and receive alerts above 100%, including a threshold such as 150%, with coverage for the changed limits and notification behavior.

Written by the indexing model from the issue text.