Issue Owners - option for disabling email notification

### Problem Statement

"We don’t want any communication via email essentially as we at COMPANY are only really reliant on Slack. Squads get alerted about errors into their own Slack alert channels, so already know they own these issues, without being told by Sentry emails. We are purely using issue ownership so squads can filter errors in Sentry by their team, but that’s it.

"Yup, having them assigned is useful for filtering issues, but we just don’t want to be notified about those automatic assignments."

User said it's too difficult to ask hundreds of engineers to turn off emails in their UserSettings and this may turn off more than just the emails from Issue Owners

### Solution Brainstorm

setting in ProjectSettings for disabling the email for this.

### Product Area

Alerts