Notifications Triggered Twice For Issue Assignees

[giteaUser]

• Gitea version (or commit ref): 1.11.0+dev-535-g60f279a86
• Git version: not needed
• Operating system: not needed
• Database (use [x]):
  • PostgreSQL
  • MySQL
  • MSSQL
  • SQLite
• Can you reproduce the bug at https://try.gitea.io:
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  • No
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• Log gist:

Description

When assigning users to issues, email and web hook notifications are triggered twice:

This line:
https://github.com/go-gitea/gitea/blob/master/routers/repo/issue.go#L1180

Calls this notification:
https://github.com/go-gitea/gitea/blob/master/services/issue/assignee.go#L50

Then after it returns, it again calls this notification:
https://github.com/go-gitea/gitea/blob/master/routers/repo/issue.go#L1186

This requires a similar fix to #9375
...

Screenshots