Expected behavior
If an app, which is flagged as "untested", is updated with a tested and valid app version, the "Enable untested app" button should instantly be replaced by the "Enable" button.
Current behavior
If an app, which is flagged as "untested", is updated with a tested and valid app version, the "Enable untested app" button is still displayed. It only vanishes if the list of apps is refreshed.
Example how an updated app is displayed after it has been updated.

After refreshing the app list it is correctly displayed:

Steps to reproduce
- Open the Apps menu.
- Choose an app which is flagged as "untested" and for which an update exists.
- Update the app and check how the app entry is looking like afterwards.
Environment
Server Configuration
OS: Linux 4.9.207
Web server: Apache2 2.4.41
Database: MariaDB 10.2.24
PHP version: 7.3.13
Nextcloud version: 18.0.0
Client Configuration
Browser: Mozilla Firefox 72.0.1
Operating system: Windows 10