Modal opening and immediately closing when enabling an extension

[SychO9]

Bug Report

Forgot to log this.

Current Behavior When enabling an extension that has a settings modal, the modal opens but immediately closes (you don't even notice it was trying to open)

Steps to Reproduce

1. Go to extension dashboard.
2. Enable an extension that has a settings modal.
3. Notice the modal opening and closing really quickly.

Expected Behavior The settings modal is supposed to open.

Environment

• Flarum version: https://github.com/flarum/core/commit/5842dd120081eb93c2ecfbebcc4f92a2280e6a69
• Webserver: apache
• Hosting environment: localhost
• PHP version: 7.4.9
• Browser: Chrome 84

Additional Context No errors in the console.

[SychO9]

Fixed with #2409