Feature Request: Alert once per environment per issue

## Summary

An additional option to send alerts based on first time an issue is seen in a given environment instead of just the first time the issue is seen.

## Motivation

We use Microsoft Teams for alerting, we currently have the following setup in Sentry Alerts:

- "env: prod" > "The event occurs" > "Send to Teams Channel: 'Alerts - Production'"
- "env: staging" > "The event occurs" > "Send to Teams Channel: 'Alerts - Staging'"
- "env: dev" > "The event occurs" > "Send to Teams Channel: 'Alerts - Dev'"

We'd like to instead only fire alerts the first time an issue is seen within a specific environment, however, the following workflow doesn't work:

- "env: prod" > "The issue is first seen" > "Send to Teams Channel: 'Alerts - Production'"
- "env: staging" > "The issue is first seen" > "Send to Teams Channel: 'Alerts - Staging'"
- "env: dev" > "The issue is first seen" > "Send to Teams Channel: 'Alerts - Dev'"

With this setup we only ever see a single alert regardless of environment. If an issue first occurs in Staging, we'll never see a second alert and third alert in the Dev or Production channels. Instead, the alerting rules should give us the flexibility to alert once per env per issue.