Fix background issue (#217)

Secretive/Controllers/LaunchAgentController.swift

@@ -23,7 +23,9 @@ struct LaunchAgentController {
         Logger().debug("Agent is not running, attempting to force launch")
         let url = Bundle.main.bundleURL.appendingPathComponent("Contents/Library/LoginItems/SecretAgent.app")
         NSWorkspace.shared.openApplication(at: url, configuration: NSWorkspace.OpenConfiguration()) { app, error in
+            DispatchQueue.main.async {
                 completion?(error == nil)
+            }
             if let error = error {
                 Logger().error("Error force launching \(error.localizedDescription)")
             } else {