Under the Actions column, you will see the below icon in green color which says, integration for that Project is in "Active" state and it will be shown as "Installed & Active" under "Integration Status" column.

You are also given a provision to Inactivate the slack integration for a particular project and when clicked on the icon, you will see a confirmation popup as below:

If you click on the "Ok" button, the icon turns red as below and the Integration Status turns to "Installed & Inactive".