Update Jellyfin.Api/Controllers/PluginsController.cs

Co-authored-by: Cody Robibero <cody@robibe.ro>

Jellyfin.Api/Controllers/PluginsController.cs

@@ -188,7 +188,7 @@ namespace Jellyfin.Api.Controllers
                 return NotFound();
             }
 
-            _installationManager.UninstallPlugin(plugin!);
+            _installationManager.UninstallPlugin(plugin);
             return NoContent();
         }